Event Details

Superconducting boron-doped nanocrystalline diamond: Fluctuations, frustration, and dimensionality

Superconductivity in boron-doped diamond was discovered in 2004 and has since been studied by various groups around the world in both single- and polycrystalline samples. Diamond doped beyond the metal-insulator transition, even when in nanocrystalline thin films, has been shown to retain the famous extreme mechanical properties of intrinsic diamond and, as such, is anticipated to be a promising material for superconducting nanoelectromechnical devices. However, over a decade since its first discovery, the superconductivity in this material is not yet well understood.

In this seminar, I will focus on the inherent granular structure of boron doped nanocrystalline diamond (BNCD) and discuss the stark impact that the granularity has on the superconducting properties. The grain size in nanocrystalline diamond can be tuned through the growth mechanism, providing a rich system in which to explore the dependence of the superconductivity on grain size, including superconducting fluctuations and a frustrated ground state.

In particular, I will discuss the low temperature transport properties of micron-sized structures. Even in patterned BNCD films that could be considered to be three-dimensional, transport measurements reveal a behaviour that is more often associated with one- or two-dimensional systems-phase slip centres and phase slip lines respectively. With reference to early fundamental studies on BNCD, I will suggest an alternative physical interpretation for these observations that arises from the granular film structure itself.

Finally, I will discuss how these microstructure-related phenomena could be harnessed and controlled to produce novel sensors and devices, and pose some open questions that could be addressed by the low temperature community.