Friday 8 November 2019, 3:00pm to 4:00pm
Open toAlumni, Postgraduates, Staff, Undergraduates
RegistrationRegistration not required - just turn up
Quantum dots in two-dimensional heterostructures
Van der Waals (vdW) heterostructures, in which a wide range of unique atomic layers can easily be combined, offer novel prospects to engineer and manipulate quantum confined states. Here I will present two approaches to this exciting prospect. I will first present Coulomb blockade in a vdW quantum dot device with tunnel coupling to a tunable Fermionic reservoir. Hybrid excitons, composed of localized quantum dot states (in WSe2) and Fermi reservoir continuum states (in graphene), are observed due to ultra-strong spin-conserving tunnel coupling resulting from an atomically thin tunnel barrier (hBN). Secondly, I will present spin-layer locking of interlayer valley excitons (IX) trapped in moiré potentials. In a heterostructure of bilayer 2H-MoSe2 and monolayer WSe2, we observe two IX species trapped in moiré potentials with distinct spin-layer-valley configurations. Due to the phenomenon of locked electron spin and layer pseudospin in bilayer 2H-MoSe2, the IX species exhibit opposite valley magnetic moments. Further, we find the 2H-MoSe2 stacking intrinsically locks the atomic registries of IXH and IXR together. Finally, we will discuss photon antibunching of moiré trapped excitons to unambiguously prove their quantum nature.
|Name||Dr Sergey Kafanov|