We study quantum devices through low-temperature electronic transport measurements. Our goal is control at the level of single charge, single flux quantum, single photon and single phonon, enabled by fundamental physical phenomena such as superconductivity, the Josephson effect, flux and charge quantisation, and quantum entanglement.

The ability to control and measure quantum states in nanoscale solid-state devices makes them a promising platform for new quantum technologies. Applications include quantum computing and quantum simulation, quantum encryption, quantum metrology, and novel sensors operating beyond the standard quantum limit.

Work within this activity includes:

• Quantum Metrology
  Superconducting and hybrid charge pumps for accurate definitions of the ampere.
• Graphene & 2D Materials
  Transport phenomena in 2D materials, including hydrodynamic flow and the superconducting proximity effect.
• Ultralow temperature thermometry and devices
  Developing the techniques required to undertake quantum transport measurements at electron temperatures below one millikelvin.
• Semiconductors
  Transport properties of narrow band-gap semiconductor heterostructures and nanostructures.
• Nanoelectromechanics
  Using nanoscale cantilevers to probe properties of quantum fluids.

Team

• Professor Yuri Pashkin
• Professor Rich Haley
• Professor Manus Hayne
• Dr Sergey Kafanov
• Dr Leonid Ponomarenko
• Dr Jon Prance
• Dr Viktor Tsepelin

Research involves the design, fabrication and characterisation of novel quantum devices that exploit the properties of III-V compound semiconductor nanostructures such as quantum dots, nanowires, quantum wells and superlattices.

A key aspect of our research is the use of advanced epitaxial growth, including:

• narrow band-gap semiconductors, such as GaSb, InAs and InSb
• self-assembled and site-controlled nanostructures
• droplet epitaxy
• hydrogenation of semiconductors
• dilute nitrides
• mismatched materials with atomically abrupt interfaces on GaAs and silicon substrates

We are developing a variety of photonic and electronic devices, including:

• mid-infrared LEDs and lasers for environmental gas sensing
• solar cells and thermo-photovoltaic devices for renewable energy generation
• GaSb quantum ring lasers for telecommunications
• low-noise photodetectors for focal plane arrays and thermal imaging
• low-voltage non-volatile memories

Our research is frequently carried out in collaboration with industry partners, including IQE, CST, Amethyst, SELEX, Huawei and others, as well as many academic groups worldwide.

Team

• Professor Tony Krier
• Professor Manus Hayne
• Professor Robert Young
• Dr Andrew Marshall
• Dr Qian Zhuang

We explore physical phenomena in advanced materials at the micron, nano and atomic scale. Our activities include:

• the development of functional 'smart' surfaces realised via novel molecular self-assembly methods
• nanoscale device characterisation
• atomic resolution imaging
• instrument development and biomaterial analysis

We develop new materials with targeted chemical, electrical, thermal and catalytic properties such as self-assembled molecular networks and novel 2D material - organic film heterostructures fabricated using a wide range of atomically precise molecular assembly techniques and spanning environments from highly controlled ultra-high vacuum conditions to liquid-phase molecular self-assembly and Langmuir-Blodgett deposition.

Underpinning this research are a wide range of characterisation methods and a long-standing interest in new instrument development. Scanning probe microscopy (SPM) is unparalleled in its ability to provide spatial resolution at the atomic and nanoscale. Our suite of SPM instruments is dedicated to high-resolution imaging, nanomechanical mapping, electrical measurement and scanning thermal microscopy, which we combine with optical spectroscopy, high-speed interferometry, x-ray photoelectron spectroscopy, synchrotron radiation studies and electronic structure calculation providing access to the full spectrum of materials properties.

Team

• Professor Oleg Kolosov
• Dr Sam Jarvis
• Dr Benjamin Robinson

Our research straddles three main disciplines: material science, quantum optics and information security. Through the hybridisation of these fields, we are driving a unique research activity; investigating the application of light-matter interfaces in low-dimensional structures for physical security applications.

We divide our research into the following themes:

• Developing components for optical quantum information processing (QIP) using low-dimensional semiconductor structures. The scalability and low-cost of semiconductor systems make them ideal for producing scalable quantum technologies.
• Harnessing the unique properties of nanostructures embedded in devices for identity provision and authentication. At the atomic level, no two objects are identical. We're developing technologies that produce east-to-read signatures based on this uniqueness, for security applications.
• Quantum light emission from heterostructures of two-dimensional materials, and associated applications. Solid-state lighting and two-dimensional materials were both the subject of recent Nobel prizes in physics. The combination of the two is driving an exciting research field.

Team

• Professor Robert Young
• Professor Manus Hayne
• Dr Benjamin Robinson

Supervisor

Dr Quian Zhuang

Description

The project will develop advanced III-V nanowires on silicon and 2D materials by molecular beam epitaxy and explore the device applications in next-generation photodetectors, fully-functional silicon photonic circuits, ultra-fast nanoelectronics and spitronics.

Supervisor

Professor Manus Hayne

Project

Computers are based on the von Neumann architecture in which the processing and memory unit are largely separated, requiring information to be shuffled to and fro, which is inefficient and creates a bottleneck. This is particularly disadvantageous for activities that are memory intensive, such as artificial intelligence and machine learning.

An alternative is in-memory computing [1, 2], in which certain algorithms are performed within the memory unit. This is less flexible than the traditional von Neumann approach, but has huge potential in terms of computational time and energy saved for memory intensive tasks involving operations that are performed huge numbers of times. These could be common logical functions such as AND and OR, or matrix-vector multiplications which comprise between 70% and 90 % of the deep-learning operations in speech, language and vision recognition [2]. Many conventional and emerging memory technologies have been investigated for in-memory computing, such as SRAM, DRAM, flash, phase change memory, resistive RAM, and very recently MRAM [3]. However, memory technologies with very fast, low-energy switching, high endurance (and low disturb) are required to fulfil the potential of in-memory computing and compete with the conventional CMOS-based approach [1].

ULTRARAM™ is a patented Lancaster memory technology with a non-volatile storage time of at least 1000 years, an endurance in excess of 10 million program/erase cycles, non-destructive read, low disturb, a switching energy that is 100 times lower per unit area than DRAM, and intrinsic sub-ns switching speeds [4]. It has huge potential as a conventional memory, but also for in-memory computing.

The PhD project will be the first to investigate ULTRARAM™ for in-memory computing. The research will involve modelling (at different scales), and designing, fabricating and testing some simple ULTRARAM™ for in-memory computing circuits to show proof of principle.

This PhD is offered in collaboration with Quinas Technology. Funding for UK students is available on a competitive basis.

[1] ‘Memory devices and applications for in-memory computing’, A. Sebastian et al., Nature Nanotechnology, 15, 529 (2020) [Link]

[2] ‘In-memory Computing for AI Applications’, E. Eleftheriou, 16^th International Conference on High-Performance and Embedded Architectures and Compilers, 18-20 January 2021 [YouTube]

[4] ‘A crossbar array of magnetoresistive memory devices for in-memory computing’, Jung et al., Nature 601, 211 (2022) [Link]

[3] ‘ULTRARAM: a low-energy, high-endurance, compound-semiconductor memory on silicon’, P. D. Hodgson, D. Lane et al. [Link]

Supervisor

Dr Quian Zhuang

Description

The project aims to develop high quality positioned quantum dot via droplet epitaxy and to explore the application in quantum optics.

Supervisor

Dr Quian Zhuang

Description

This project aims to develop broadly tunable mid-infrared VCSEL devices and explore its use for interferometry. This will be achieved through the use of semiconductor type II cascade structures with an external cavity, to provide VCSEL with tenability of ~ 1 um. Precise tuning of the emitting wavelength of VCSEL pairs through self-heating phenomena will be explored to investigate the use in interferometry.

The project will be closely incorporated with MIRICO, a company dedicated in gas analysing based on laser interference induced by phase shift. The success of the project will provide a completely new technology for gas analysing, which can provide significantly improved accuracy, response time and compactness, with massively reduced cost. MIRICO will provide in-kind input, e.g. investigate the interferometry features from VCSEL pairs that commercially in the market and assess Lancaster VCSELs and their interferometry, and offer secondment opportunities for the student to develop and use their optical bench setup to assess Lancaster VCSEL. The student will be trained for the use of companies’ facilities and will be supervised by senior engineers from the company; the student will also learn about the management approaches of the companies, in particular with MIRICO which is experienced in managing EU and Innovate UK research projects. The student should also develop the skills in lecturing – he/she will be the key contact to present the research outcomes to the companies and to intake the feedback from companies to achieve the next milestone.

Also, there will be a good chance formulating a joint research proposal including Physics, LEC and MIRICO for a bid to the forthcoming UKRI research program aiming to tackle climate change and driving clean growth (focused on the theme of Clean Air). The PhD candidate will be in a consortium including physicists, environmental scientists and instrumental engineers if the bid is successful.

Supervisor

Professor Robert Young

Description

Securing the digital electronic devices in our lives, from computers to smart home appliances and safety critical systems, is becoming increasingly challenging. As technology develops, nefarious parties have access to greater resources, and as device get more complex the probability of security-related bugs making their way into released products increases.

At Lancaster we have a pioneering vision of using quantum technologies to address this security challenge. Fundamental rules of quantum mechanics can be exploited to create devices with provable security metrics, including quantum key distribution systems (for security communications) [1], quantum random number generators (for unpredictable session keys) [2] to physical unclonable functions (for identification and anti-counterfeiting) [3]. The devices can then be combined to create secure systems.

PhD projects are available to develop and integrate quantum security devices, working with the fantastic facilities in Lancaster University’s Quantum Technology Centre [4]. There are also opportunities for excellent students to work with directly with our spin-out company, Quantum Base Ltd; funding is available on a competitive basis.

[1] “Quantum information to the home” - https://doi.org/10.1088/1367-2630/13/6/063039

[2] “Extracting random numbers from quantum tunnelling through a single diode” - https://doi.org/10.1038/s41598-017-18161-9

[3] “Using intrinsic properties of quantum dots to provide additional security when uniquely identifying devices” - https://doi.org/10.1038/s41598-022-20596-8

[4] https://www.lancaster.ac.uk/quantum-technology/

Supervisor

Dr Rostislaw Mikhaylovskiy

Description

Finding a fundamentally new way for data processing in the fastest and most energy efficient manner is a frontier problem for applied physics and technology. The amount of data generated every second is so enormous that the heat produced by modern data centres has already become a serious limitation to further increase their performance. This heating is a result of the Ohmic dissipation of energy unavoidable in conventional electronics. At present, the data industry lacks a solution for this problem, which in future may contribute greatly to the global warming and energy crisis.

An emerging alternative approach is to employ spin waves (magnons) to realize waveform-based computation, which is free from electronic Joule heating. However, the present realization of this approach, called magnonics, uses electric currents to generate and modulate magnons. In the course of this PhD project we will work towards replacement of the current by light using antiferromagnetic materials, in which spins precess on a picosecond (one trillionth of a second) timescale and strongly couple to electro-magnetic waves [1]. Yet, the antiferromagnetic THz magnons remain practically unexplored [2].

To excite THz magnons we will use ultrashort strong electro-magnetic fields produced either by table-top ultrafast lasers. We will push the driven spin dynamics into strongly nonlinear regime required for practical applications such as quantum computation or magnetization switching [3]. We will investigate nonlinear interaction of intense and highly coherent magnons with an eye on reaching regimes of auto-oscillations, nonlinear frequency conversion and complete magnetization reversal [4].

This interdisciplinary project at the interface between magnetism and photonics offers training in ultrafast optics, THz and magneto-optical spectroscopies as well as in physics of magnetically ordered materials. Also there will be opportunities for travel and experiments using THz free-electron laser facilities such as FELIX (Nijmegen, Netherlands) and TELBE (Dresden, Germany).

Interested candidates should contact Dr Rostislav Mikhaylovskiy Dr Rostislav Mikhaylovskiy for further information. Funding is available on a competitive basis.

[1]. K. Grishunin , T. Huisman, G. Li, E. Mishina, Th. Rasing, A. V. Kimel, K. Zhang, Z. Jin, S. Cao, W. Ren , G.-H. Ma and R. V. Mikhaylovskiy. Terahertz magnon-polaritons in TmFeO₃. ACS Photonics 5, 1375 (2018).

[2]. J. R. Hortensius, D. Afanasiev, M. Matthiesen, R. Leenders, R. Citro, A. V. Kimel, R. V. Mikhaylovskiy, B. A. Ivanov & A. D. Caviglia. Coherent spin-wave transport in an antiferromagnet. Nature Physics 17, 1001 (2021).

[3]. S. Baierl, M. Hohenleutner, T. Kampfrath, A. K. Zvezdin, A. V. Kimel, R. Huber, and R. V. Mikhaylovskiy. Nonlinear spin control by terahertz driven anisotropy fields. Nature Photonics 10, 715 (2016).

[4] S. Schlauderer, C. Lange, S. Baierl, T. Ebnet, C. P. Schmid, D. C. Valovcin, A. K. Zvezdin, A. V. Kimel, R. V. Mikhaylovskiy and R. Huber. Temporal and spectral fingerprints of ultrafast all-coherent spin switching. Nature 569, 383 (2019).

Supervisor

Dr Samuel Jarvis

Description

Project summary – The goal of this PhD project is to develop highly ordered and structurally stable molecular devices. The growth of thermally and mechanically stable molecular nanostructures is a major challenge for retaining the quantum mechanical properties of molecules in real-world and demanding environments. This is especially important in nanoelectrical devices where heat and stress can damage the molecular structure, causing device failure. This PhD project aims to overcome this challenge by developing new methods for step-by-step (atom-by-atom) on-surface synthesis of covalently stabilised molecular wires and devices. Achieving this goal will address a major outstanding challenge in translating functional molecular polymers to technologically relevant materials.

Background – Thin-film molecular layers are exceptionally important for introducing high degrees of functionality to materials. Molecules can be designed with a multitude of different physical properties, ranging from high electrical conductivity, catalytic activity, tuneable optical properties, and much more [1]. These properties are determined by the electronic structure of a molecule, making them well suited for applications in quantum technologies. In particular, on-surface polymerization restricted to one and two dimensions has received considerable recent attention [2]. Not only does covalent cross-linking of molecules greatly increase their stability, on-surface polymerization also enables the growth of unique molecular structures often otherwise impossible to synthesize, including graphene nano ribbons used as molecular wires [3].

At present, the vast majority of molecular nanoscale synthesis is limited to catalytically active metal substrates, where the catalyst metal is required to activate the polymerisation reaction. This results in strong surface coupling causing molecular distortion, orbital broadening, and electrical short-circuits, thus detrimentally affecting molecular properties and severely restricting their application in physical devices. In order to fully realise nanoscale molecular devices, we must instead fabricate molecular wires directly on semiconducting substrates such as SiO₂, where they can be directly integrated into nanoelectronic devices. To do this, we will build on recent findings [4] highlighting the potential to fabricate nanoscale molecular structures directly on surfaces using so-called atomic quantum clusters (AQCs).

Project Outline – This project will explore methods to direct the assembly and growth of functional molecules into nanoscale structures and devices. We will study how single molecules with well-defined quantum mechanical properties can be ‘linked’ together into rigid 1D molecular wires or 2D molecular networks, starting with porphyrin and graphene nanoribbon based wires. Single molecule and atomic scale properties will be studied with images of their detailed atomic and electronic structure (with resolution better than 0.1nm). The resulting molecular structures will provide an exciting playground to develop our fundamental understanding of quantum behaviour and molecular interactions at the atomic scale, and ultimately, provide new routes for developing nanoscale electronic devices such as field effect transistors (FETs) [5].

The selected student will have the opportunity to become trained in a broad range of techniques to study a variety of nanoscale materials. This will involve advanced scanning probe microscopy methods capable of imaging single atoms and characterising nanoscale electronic and chemical properties. This work will take place in world-leading facilities including Lancaster’s Quantum Technology Centre and the award winning IsoLab, providing some of the most advanced environments for characterisation in the world. You will work in a vibrant research group, whose research has been shortlisted for the Times Higher Education award for ‘STEM project of the year’ in 2019. You will also become highly trained in nanoscale material fabrication, ultra-high vacuum technology, X-ray spectroscopy, clean room usage, device testing, and use nano-fabrication tools to prepare devices for integration with embedded systems. Students are also expected to publish high impact journal publications and present their work at international meetings and conferences, and will receive opportunities and training for personal and research development.

Interested candidates should contact Dr Samuel Jarvis for further information.

[1] T. Kudernac, S. Lei, J. A. A. W. Elemans, and S. De Feyter, Chem. Soc. Rev. 38, 402 (2009).

[2] L. Grill and S. Hecht, Nature Chemistry, 12, 115 (2020).

[3] P. Ruffieux, S. Wang, B. Yang, C. Sánchez-Sánchez, J. Liu, T. Dienel, et al., Nature 531, 489 (2016).

[4] L. Forcieri, Q. Wu, A. Quadrelli, S. Hou, B. Mangham, N.R. Champness, D. Buceta, M.A. Lopez-Quintela, C.J. Lambert, S.P. Jarvis, Nature Chemistry (under review), (2022).

[5] J.P. Llinas, A. Fairbrother, G.B. Barin, W. Shi,. K. Lee, S. Wu, et al., Nature Communications, 8, 633 (2017).

Supervisor

Dr Michael Thompson

Description

There is a growing demand for electronic components that operate are cryogenic temperatures, from analogue amplifiers to digital control circuits for quantum computing. Existing electronic components are manufactured using semiconductors, mostly silicon, that either don’t work at all, or work poorly at very low temperatures. Two-dimensional materials, such as graphene, have been used for building transistors and even more complex components, with comparable performance to existing semiconductors. However, unlike existing semiconductor components, these materials continue to function as well, if not better, at very low temperatures. The aim of this project is to build cryogenic electronics using these 2D materials, in particular, using commercially available wafer-scale graphene to build analogue amplifiers.

This project will make use of Lancaster’s cleanroom for fabrication and the IsoLab facility for device characterisation. IsoLab is equipped with a dilution refrigerator capable of cooling devices down to 10 mK and is housed inside an electromagnetically shielded room. The filtered mains circuits and dedicated ground nest make this facility the ideal location for testing low-noise cryogenic electronics.

For this project, a student will learn to fabricate nanoelectronic devices using both 2D materials and semiconductors and characterisation of these inside a cryogenic refrigerator. This work is closely linked to existing collaborations with the National Graphene Institute in Manchester and the European Microkelvin Platform project and the student will have the opportunity to engage with these collaborations.

You are expected to have a strong interest and preferably knowledge in:

electrical measurements of nanoscale devices

cryogenic techniques

nanofabrication

data acquisition using Python or similar

Supervisor

Dr Michael Thompson

Description

Josephson junctions are a key component in superconducting electronics and are used in superconducting qubits, superconducting quantum interference devices, Josephson parametric amplifiers and many more. Junctions formed with graphene can have their critical current tuned using a local gate, creating junctions whose properties can be varied during operation. This has the potential to enhance existing technologies or open up possibilities for creating entirely new devices.

While such junctions have already been demonstrated, these use exfoliated graphene flakes, which is not a scalable technology and makes implementation of these junctions impractical for applications outside of fundamental research. Graphene is available in large areas, grown by chemical vapour deposition and while the quality is not as high as exfoliated flakes, it is possible to make junctions using this material. This opens up the opportunity for building superconducting electronics with tunable junctions at scale. This project aims to develop a process for fabricating graphene-superconductor junctions with low resistance contacts using CVD graphene and once established, design and build electronics devices.

This project will make use of Lancaster’s cleanroom for fabrication and the IsoLab facility for device characterisation. IsoLab is equipped with a dilution refrigerator capable of cooling devices down to 10 mK and is housed inside an electromagnetically shielded room. The filtered mains circuits and dedicated ground nest make this facility the ideal location for testing low-noise cryogenic electronics. For this project, a student will learn to fabricate nanoelectronic devices using 2D materials and characterisation of these inside a cryogenic refrigerator.

You are expected to have a strong interest in:

• electrical measurements of nanoscale devices
• cryogenic techniques
• nanofabrication
• data acquisition using Python or similar

Supervisor

Dr Jonathan Prance

Project description

The ability to cool materials to millikelvin temperatures has been the foundation of many breakthroughs in condensed matter physics and nanotechnology. At this frontier, quantum behaviour can be studied by making devices smaller and colder, increasing coherence across the system. The goal of this project is to apply a new technique – on-chip demagnetisation refrigeration – to reach temperatures below 1 millikelvin in a range of nanoelectronic structures. This will open a new temperature range for nanoscale physics.

As experiments are pushed into the sub-millikelvin regime, it becomes increasingly difficult to measure and define the temperature of a material or device. The thermal coupling between various sub-systems in can be extremely small; for example, the electrons in the metal wires contacting an on-chip structure can be at a different temperature to the electrons in the chip, the phonons in the chip, and the apparatus that you are using to cool it. This situation calls for a variety of thermometry techniques, each suited to measuring the temperature of a different physical system. The thermometers must also have extremely low heat dissipation and excellent isolation from the room temperature environment. This project will include the development of new and existing thermometry techniques that are suitable for sub-millikelvin temperatures.

Devices will be produced in the Lancaster Quantum Technology Centre cleanroom, and by our collaborators. Experiments will be conducted using the cutting-edge facilities of the Ultralow Temperature Physics group at Lancaster.

You are expected to have a strong interest in and preferably knowledge of:

• electrical measurements of nanoscale devices
• cryogenic techniques
• nanofabrication
• data acquisition using Python or MatLab

Supervisor

Professor Oleg Kolosov

Project description

The new PhD project is announced at Lancaster University in collaboration with the National Graphene Institute. The project focuses on the exploration of cutting-edge fundamental and applied science of “mixed physics” phenomena – electromechanical, electronic, thermal and thermoelectric - in the explosively expanding area of novel nanostructured two-dimensional materials (2DMs) and their heterostructures.

The recently discovered 2DMs – one atom thick van der Waals-bound perfect atomic layers such as graphene and transition metal dichalcogenides (TMD’s) - MoS2, Nb2Se3, InSe, etc, open unique possibilities for novel electronics, sensors and energy generation and storage. This class of materials offers unique and nature-leading physical properties – relativistic type electron mobility, the highest to the lowest known thermal conductivities, exceptional flexibility while record strength in mechanical properties, etc.

The project focuses on the largely unexplored area of 2DM’s where physical phenomena of different nature meet – mechanical and electrical, thermal and electronic, mechanical and thermal, initiating beyond-state-of-the-art performing thermoelectrics, nanoscale actuators, super-efficient electronics, memories and sensors. E.g. the highest known in nature thermal conductivity of graphene allows to precisely channel nanoscale heat in advanced processors, new TMD heterostructures have unique potential as advanced thermoelectric materials, and exceptional mechanical stiffness and low density of graphene and hexagonal boron nitride, coupled with low losses, allows to design in quantum nanoelectromechanical sensors with ultimate sensitivity limited only by the quantum mechanics laws.

The successful applicant will work at Lancaster University Physics Department within one of the world-leading groups in the exploration of physical properties of 2DM’s using scanning probe microscopy (SPM) where novel phenomena of geometrical thermoelectricity (GTE) in graphene and unique nanomechanics of domains in 2D materials heterostructures were discovered.

The project will target the manufacture of novel 2DM nanostructures including nanoconstrictions, heterostructures, suspended membranes and superconductor – 2DM devices using the state-of-the-art e-beam lithography equipped Lancaster Quantum Technology Centre facilities of National Graphene Institute and National Physical Laboratory. The developed nanostructures are studied using state-of-the-art SPMs combined with ultra-high frequency ultrasonic excitation, GHz range Laser Doppler vibrometry and super-sensitive optical interferometry, and microwave superconductor transport techniques, utilising world-leading European Microkelvin Platform (EMP) and ultra-low-nose IsoLab facilities housed at Lancaster Physics.

The Physics Department is holder of Athena SWAN Silver award and Institute of Physics JUNO Championship status and is strongly committed to fostering diversity within its community as a source of excellence, cultural enrichment, and social strength. We welcome those who would contribute to the further diversification of our department.

Contact

Professor Oleg Kolosov o.kolosov@lancaster.ac.uk for any additional enquiries. You can also apply directly stating the title of the project and the name of the supervisor.

Supervisor

Professor Manus Hayne

Project description

It is obvious that physical scaling of the transistors underpinning digital electronics has ultimate limits. As these have been approached, increasing the size of the chip had been used to maintain Moore’s law [1]. However, this is bounded by wafer size, and has expensive yield and geometry issues. Furthermore, power constraints have restricted clock speeds for years, and there is concern about the huge amounts of electricity that computing, especially datacentres, consumes [2]. Capacity cannot exponentially increase indefinitely, but radical new approaches are nevertheless required for information and communication technologies of the future.

The PhD project will further develop a patent-pending alternative approach to digital logic [3] that abandons the CMOS paradigm underpinning computing. Practical implementation of digital logic requires pairs of devices that display complementary, or opposite, behaviour, i.e., the same input will turn one device on and its complementary partner off. This is currently achieved by pairs of nMOS and pMOS (MOS = metal oxide semiconductor) field-effect transistors, hence CMOS, where C stands for complementary. In our concept, logical complementarity, and hence function, is achieved by a single device where an electron reservoir is sandwiched between two normally-off channels. Application of a positive gate voltage to the top of the device will pull the electrons to the top channel, turning it on, whilst the bottom channel remains off. Similarly, application of a negative gate voltage to the top of the device will push the electrons to the bottom channel, turning it on, whilst the top channel remains off. This device has a number of intrinsic advantages over CMOS, it is twice as compact, highly symmetric and expected to have lower dissipation.

The feasibility of the concept has been demonstrated via simulations and prototype devices in an existing PhD project. The scope of the new work involves next steps such as fabrication and testing of more complex logic gates and circuits, scaling of devices, low-temperature testing and integration with ULTRARAM™ [4].

This PhD is offered in collaboration with Quinas Technology. Funding for UK students is available on a competitive basis.

[1] ‘Moore’s law’, Wikipedia [Link].

[2] ‘How to stop data centres from gobbling up the world’s electricity’, N. Jones, Nature 561, 163-166 (2018) [Link].

[3] ‘Logic gate’, M. Hayne and J.J. Hall, patent pending PCT/GB2023/051493 (2022).

[4] ‘ULTRARAM: a low-energy, high-endurance, compound-semiconductor memory on silicon’, P. D. Hodgson, D. Lane et al. [Link]

Supervisor

Professor Manus Hayne

Project description

Vertical-cavity surface-emitting lasers (VCSELs) are high-speed, compact (low-cost) laser diodes used in laser printing, datacoms and other applications. Their implementation in the Apple iPhone X for facial recognition and motion sensing was soon replicated by other smartphone manufacturers, stimulating a growth in the VCSEL market from $775M in 2015 to an expected $4.7bn in 2024, a compound annual growth rate of 22% [1]. Nevertheless, many consumers and thus manufacturers, don’t like the small cut-out section at the top of the screen that is necessary for the implementation of the VCSEL arrays, preferring to place the VCSEL below the screen. However, achieving this requires VCSELs that emit beyond 1380 nm. Indeed, there are a host of telecoms-related and other applications such as LiDAR that have yet to benefit from VCSELs that emit in the telecoms range (1260 to 1625 nm).

VCSELs work by implementing the mirrors required for the laser cavity in repeated alternating layers of GaAs and Al_x­Ga_1-xAs, which have differing refractive indices, to make distributed Bragg reflectors that exploit interference effects. The use of GaAs/Al_x­Ga_1-xAs is strongly preferred as there is minimal lattice mismatch, despite the refractive index contrast, allowing ~100 layers to be grown with high quality. The problem is that the conventional method of extending the wavelength, via the introduction of In into the quantum wells in the active region, generates strain that limits the emission to wavelengths below 1000 nm.

The project will build on successful collaborative work between IQE and Lancaster developing telecoms wavelength GaSb quantum ring (QR) VCSELs [2]. The objective is to push the emission wavelength beyond 1380 nm and will involve the design, growth, processing and testing of individual VCSEL devices and VCSEL arrays.

This PhD is offered in collaboration with IQE. Funding for UK students is available on a competitive basis.

[1] ‘Vertical-cavity surface-emitting laser (VCSELs) market’, Transparency Market Research [Link].

[2] ‘Vertical-cavity surface-emitting laser’, M. Hayne and P. Hodgson US, Europe, Japan and S Korea patent [Link].

Supervisor

Professor Manus Hayne

Project description

ULTRARAM™ [1,2] is an ultra-efficient, award-winning [3] memory technology invented in the Physics Department at Lancaster that combines the non-volatility of flash with the speed and endurance of dynamic random access (DRAM). Such properties are characteristic of a so-called ‘universal memory’ that has the capability to be implemented in any application, but it is likely that at least initially, ULTRARAM will be used in high-value applications where its many beneficial attributes of speed, energy efficiency, tolerance of extremes in temperature etc. outweigh the inevitably large cost per bit of small-scale production. Irrespective of the details of the first products, it will be necessary to fabricate and test large numbers of devices in increasingly large arrays and/or with smaller feature sizes in order to understand device variation, gathering statistics for a range of parameters such as yield, retention, endurance, logical contrast etc.. This will be the remit of the PhD project, placing it at the cutting edge of the development of a highly-disruptive memory technology.

This PhD is offered in collaboration with Quinas Technology. Funding for UK students is available on a competitive basis.

[1] www.ultraram.tech.

[2] ‘ULTRARAM: a low-energy, high-endurance, compound-semiconductor memory on silicon’, P. D. Hodgson, D. Lane et al. [Link].

[3] ULTRARAM Start-up Wins Best of Show Memory Technology Award in Silicon Valley - Lancaster University

Supervisor

Dr Samuel Jarvis

Project summary – The goal of this PhD project is to help realise a new generation of switchable molecular devices with the potential to fulfil societal needs for flexible energy harvesting materials, low-power neuromorphic computing, smart textiles, and self-powered patches for healthcare. The possibility of creating these exciting materials derives from a series of world firsts by the supervisory team, demonstrating that room-temperature quantum interference effects can be scaled up from single molecules into molecular layers with the potential to translate quantum interference effects into technologically relevant materials.

Background – Thin-film molecular layers are exceptionally important for introducing high degrees of functionality to materials. Molecules can be designed with a multitude of different physical properties, ranging from high electrical conductivity, catalytic activity, tuneable optical properties, and much more [1]. These properties are determined by the electronic structure of a molecule, making them well suited for applications in quantum technologies. In particular, a technique called on-surface polymerization has received considerable recent attention due to its ability to create unique and stable 1D and 2D molecular structures with an exciting range of quantum mechanical properties [2]. This project is an exciting opportunity to realise these new materials as part of a recently awarded £7m programme of research bringing together a world leading team in molecular electronics [3].

Project Outline – This project will explore methods for surface growth and characterisation of molecular thin films designed to optimise thermoelectric and memristive properties. The successful candidate will develop new methods to prepare highly ordered molecular films including the use of on-surface reactions that can be used to link together molecules with well-defined quantum mechanical properties into rigid 1D molecular wires or 2D molecular networks. Single molecule and atomic scale properties will be studied with Scanning Tunnelling Microscopy (STM) which provide images of their detailed atomic and electronic structure (with resolution better than 0.1nm). The resulting molecular structures will provide an exciting playground to develop our fundamental understanding of quantum behaviour and molecular interactions at the atomic scale, and ultimately, provide new routes for developing nanoscale molecular electronic devices.

The selected student will have the opportunity to become trained in a broad range of techniques to study a variety of nanoscale materials. This will involve advanced scanning probe microscopy methods capable of imaging single atoms and characterising nanoscale electronic and chemical properties. This work will take place in world-leading facilities including Lancaster’s Quantum Technology Centre and the award winning IsoLab, providing advanced environments for atomic scale characterisation. You will also become highly trained in nanoscale material fabrication, ultra-high vacuum technology and X-ray spectroscopy. Students are also expected to publish high impact journal publications and present their work at international meetings and conferences, and will receive opportunities and training for personal and research development.

[1] T. Kudernac, S. Lei, J. A. A. W. Elemans, and S. De Feyter, Chem. Soc. Rev. 38, 402 (2009).

[2] L. Grill and S. Hecht, Nature Chemistry, 12, 115 (2020).

[3] https://www.lancaster.ac.uk/news/7m-award-for-quantum-engineering-of-energy-efficient-organic-smart-materials.

For more information, please visit the QMol website

Supervisor

Dr Benjamin Robinson

Project summary: This is an experimental project, based in the Department of Physics at Lancaster University and is associated with the recently awarded, Lancaster-led, £7.1M EPSRC programme grant, Quantum engineering of energy-efficient molecular materials (QMol) [1]. The project will help realise a new generation of switchable molecular devices with the potential to fulfil societal needs for flexible energy harvesting materials, low-power neuromorphic computing, smart textiles, and self-powered patches for healthcare.

The goal of this project is to bring together new materials synthesised by colleagues within QMol and world-leading characterisation capabilities developed at Lancaster University to realise a new generation of high-performance materials which demonstrate highly tuneable quantum properties at room temperature.

The possibility of creating these exciting materials derives from a series of world firsts by the QMol team, demonstrating that room-temperature quantum interference effects can be scaled up from single molecules into molecular layers [2,3], potentially translating quantum interference effects into technologically relevant materials.

Background: Waste heat generated by information and computing technologies (ICT) is expected to reach 30% of US electricity consumption by 2025 and is widely recognised as being unsustainable. If low-energy computing paradigms based on neuromorphic computing could be realised, which efficiently process large amounts of data with low power consumption, then much of this waste heat could be avoided. In addition, if thermoelectric (TE) energy harvesters could be developed, which perform well at relatively low temperatures (<150^oC), then waste heat from ICT could be converted back into useful electricity. Energy harvested from the environment and sources such as the human body could also be used to power the internet of things and wearable devices, with engineered thermal management relevant to applications in healthcare, fashion and high-performance clothing.

This project will contribute to these technological challenges and the associated societal and economic benefits by helping to realise large area, switchable thin-film materials and devices on rigid and flexible substrates, designed for TE energy harvesting, cooling, sensing, thermal management and memristive switching. This overarching research challenge will be met, in part, by utilising quantum interference (QI), which introduces additional dynamical range by suppressing current flow at low bias and allows fine control of electrical and thermal conductance [4].

Project Outline: This project will focus on the thin film growth of novel organic/organometallic compounds by molecular self-assembly and Langmuir-Blodgett deposition and their subsequent characterisation by a range of surface science techniques including scanning probe microscopy.

The project is predominantly experimental and you will gain interdisciplinary expertise spanning materials design, thin film fabrication, and nanoscale characterisation. You will benefit from Lancaster’s molecular thin film fabrication capabilities and a suite of state-of-the-art scanning probe microscopes to explore the physical processes of thermal and electrical transport in deposited ultra-thin structures. The compounds will be supplied by colleagues in the Departments of Chemistry at Oxford University and Imperial College, London. There will also be opportunities for you to work with colleagues from the Department of Physics at Imperial College to translate your thin films to practical device architectures.

Research Environment: You will benefit from a vibrant working environment and will be part of the QMol consortium incorporating partners across nine leading Universities and 11 industry partners. Through QMol, you will have the opportunity to develop skills in interdisciplinary working through close collaboration with colleagues studying the theory of quantum transport and device fabrication, as well as industry partners from both SMEs and multinational corporations.

You will be trained and supported in other academic skills such as the preparation of high-impact journal publications, and presenting your work at international meetings and conferences, and you will receive opportunities and training for personal and research development. In addition, you will have the opportunity to join in local and national outreach and engagement activities.

Lancaster University is a leading UK university and the Physics Department at Lancaster University is one of the top in the UK for research. REF2021 rated 98% of our research outputs as world-leading or internationally excellent. The Department is ranked 4th in the UK for Physics in the Guardian University League Tables 2023.

The Department is committed to family-friendly and flexible working policies. We are also strongly committed to fostering diversity within our community as a source of excellence, cultural enrichment, and social strength. We hold an Athena SWAN Silver award and Institute of Physics Juno Champion status. We welcome those who would contribute to the further diversification of our department.

The Candidate: This project will ideally suit a candidate who has an interest in interdisciplinary experimental nanoscience. Knowledge of nanomaterials or experience in either quantum transport, scanning probe microscopy and/or self-assembly of organic monolayers would be advantageous but not compulsory as full training in a wide variety of techniques will be given.

You will need to be highly motivated and be able to work as part of a team, ensuring that key milestones are reached. You will be expected to lead discussions and give regular research updates in person with the group leader and in wider research group meetings with the project consortium. The ability to plan your own workload and keep accurate scientific records is important.

General eligibility criteria: This is a highly interdisciplinary project operating at the interface of Physics, Chemistry and device engineering.  Applicants would normally be expected to hold a minimum of a UK Honours degree at 2:1 level or equivalent in Physics, Chemistry, Materials Science or a related area.

Enquiries: Interested applicants are welcome to get in touch to learn more about the PhD project. Please contact Dr Benjamin Robinson, for more information.

[1] https://www.lancaster.ac.uk/news/7m-award-for-quantum-engineering-of-energy-efficient-organic-smart-materials.

[2] Wang, X.; et al. Scale-Up of Room-Temperature Constructive Quantum Interference from Single Molecules to Self-Assembled Molecular-Electronic Films, Journal of the American Chemical Society 142 (19) 8555–8560 (2020)

[3] Bennett, T.L.R.; et al. Multi-component self-assembled molecular-electronic films: towards new high-performance thermoelectric systems, Chemical Science 13, 5176-5185 (2022)

[4] Hamill, J.M.; et al. Quantum Interference and Contact Effects in the Thermoelectric Performance of Anthracene-Based Molecules, The Journal of Physical Chemistry C, 127 (15), 7484–7491 (2023)

Supervisors

• Dr Benjamin Robinson (Physics)
• Dr Sam Jarvis (Physics)
• Dr Jonathan Ward (Chemistry)

Dates

• Deadline for applications: 15th March 2024
• Provisional Interview Date: Mar - April 2024
• Start Date: October 2024

Project description

Green thermoelectricity – the sustainable generation of electricity from waste heat - has the potential to be a key enabling technology to combat climate change in the roadmap to the UK’s target of net zero greenhouse gases by 2050. However, current inorganic thermoelectric materials are inefficient, brittle, toxic and often comprised of critical raw materials. This project seeks to address these challenges through a new class of high-efficiency organic thermoelectric materials.

The programme is interdisciplinary and will span activities in Physics and Chemistry. The PhD student will primarily focus on developing new organic materials characterised in the Physics Department (Robinson and Jarvis) and synthesised in the Chemistry Department (Ward). The materials developed will exhibit room-temperature quantum interference effects, which have been shown to boost thermoelectric performance when assembled in ultra-thin flexible films. This project builds on a track record of high-impact publications led by the supervisors and their collaborators.

The project is predominantly experimental and the PhD student will gain interdisciplinary expertise spanning materials synthesis, molecular electronics, green energy materials, and scanning probe nanoscale characterisation. The student will benefit from access to advanced materials characterisation capabilities including scanning probe microscopy (SPM) housed in Lancaster’s state-of-the-art low noise facility IsoLab, X-ray photoelectron spectroscopy (XPS), and bespoke material synthesis.

The student will benefit from a vibrant working environment and will be part of the national QMol (Quantum engineering of energy-efficient molecular materials) network, a recently funded £8.6M programme led by LU incorporating partners across nine leading Universities and 11 industry partners. Through QMol, the student will have the opportunity to develop skills in interdisciplinary working through close collaboration with colleagues studying the theory of quantum transport, and device fabrication, as well as industry partners from both SMEs and Multinational corporations.

General eligibility criteria

This is a highly interdisciplinary project operating at the interface of Physics, Chemistry and device engineering.  Applicants would normally be expected to hold a minimum of a UK Honours degree at 2:1 level or equivalent in Physics, Chemistry, Materials Science or a related area.

Project-specific criteria

This project will ideally suit a candidate who has an interest in interdisciplinary experimental nanoscience. Knowledge of nanomaterials or experience in either quantum transport, scanning probe microscopy and/or self-assembly of organic monolayers would be advantageous but not compulsory as full training in a wide variety of techniques will be given. The candidate is expected to successfully work as part of a team, with good interpersonal skills, and to successfully complete research projects suitable for the award of a PhD in physics, including publications in high-impact peer-reviewed articles.

Studentship funding

A tax-free stipend will be paid at the standard UKRI rate; currently £18,622. This is a fully funded studentship of 3.5 years for UK/Home students.

Enquiries

Interested applicants are welcome to contact Ben Robinson at b.j.robinson@lancaster.ac.uk to learn more about the PhD project.

Further reading

• Wang, X.; et al. Scale-Up of Room-Temperature Constructive Quantum Interference from Single Molecules to Self-Assembled Molecular-Electronic Films, Journal of the American Chemical Society 142 (19) 8555–8560 (2020)
• Bennett, T.L.R.; et al. Multi-component self-assembled molecular-electronic films: towards new high-performance thermoelectric systems, Chemical Science 13, 5176-5185 (2022)
• Hamill, J.M.; et al. Quantum Interference and Contact Effects in the Thermoelectric Performance of Anthracene-Based Molecules, The Journal of Physical Chemistry C, 127 (15), 7484–7491 (2023)

Application process

1. Download the Natural Sciences Funded PhD Application Form and Natural Sciences Funded PhD Reference Form‌.
2. Complete the Application Form, renaming the document with your 'Name and Application Form' e.g., Joe Bloggs Application Form
3. Submit the completed Application Form and a CV to naturalsci@lancaster.ac.uk
4. Please note only Word or PDF files are accepted
5. Rename the referee form with your ‘Name and Reference’, e.g., Joe Bloggs Reference. Send the renamed reference form to two referees and request them to forward the referee document to naturalsci@lancaster.ac.uk
6. Please note only Word or PDF files are accepted. It is important that you ensure references are submitted by the closing date or as soon as possible
7. You will receive a generic acknowledgement in receipt of successfully sending the application documents.
8. Please note that only applications submitted as per these instructions will be considered
9. Please note that if English is not your first language, you will be required to provide evidence of your proficiency in English. This evidence is only required if you are offered a funded PhD and is not required as part of this application process
10. Please note that if you do not hear from us within four weeks of the closing date, then you have been unsuccessful on this occasion. If you would like feedback on your application, please contact the supervisors of the project

Supervisor

Professor Oleg Kolosov

Project details

The new PhD project in fundamental and applied physics is announced at Lancaster University Quantum Technologie Centre (LQTC) in collaboration with the National Scientific Research Centre “Demokritos” (NCSRD) in Athens, Greece, and National Graphene Institute (NGI), UK, the birthplace of Graphene, as part of the announced collaborative European Research Council project.

The challenging and high-reward PhD project will target fundamental physics in two-dimensional (2D) materials, their nanostructures, and 2D-3D materials devices developing novel principles of advanced quantum and nanoscale energy management devices. In particular, the project will investigate largely unexplored fundamental links between electronic and phononic heat transport, electrical and nanomechanical phenomena, and thermal-electrical-mechanical energy conversion in the 2D nanostructures. The project outcomes will lead to highly efficient thermoelectric and electrocaloric devices, beyond-state-of-the-art on-chip cooling, and highly sensitive photons and phonons detectors, approaching quantum limits.

The successful applicant will work in experimental research at Lancaster University Quantum Technology Centre (LQTC) in one of the world-leading groups in the exploration of physical properties of 2DM’s using scanning probe microscopy (SPM), in direct interaction with NCSRD in Athens, the world leader in molecular beam epitaxy synthesis of 2D materials, and National Graphene Institute producing unique 2D material hetero and nanostructures. The applicant will have the opportunity to spend some time in Athens and at NGI, and collaborate with leading experimental and theoretical scientists in the field. The applicant is expected to have an excellent academic record in the Physics, Material Science or Electrical Engineering, with good experience in advanced experimentation, and good analytical skills.

The Physics Department is in the top 10 of UK Physics Departments (#4 by Guardian and Sunday Times rating and #7 by Good University Guide). It is a holder of Athena SWAN Silver award and Institute of Physics JUNO Championship status and is strongly committed to fostering diversity within its community as a source of excellence, cultural enrichment, and social strength. We welcome those who would contribute to the further diversification of our department.

Applicants are expected to have the equivalent of a first (1) or upper second (2.1) degree class in Physics or Astrophysics, supplemented by a relevant Master's-level qualification. Potential applicants are invited to apply to the physics department stating the title of the project and the name of the supervisor.

Contact Professor Oleg Kolosov for any additional enquiries

Funding note

The funding for this project is restricted to UK residents and will cover national and international secondments to the NGI and NCSRD in Athens.