Supercurrent and Heat Flow in Ballistic Graphene

The talk will focus on layered structures in which graphene is stacked between hexagonal boron nitride crystals (hBN), and where electrons can travel for many micrometers before experiencing any scattering or decoherence.
I will first describe “ballistic” Josephson currents induced in graphene by placing it in proximity to a superconductor [1]. These currents persist even in the presence of high magnetic fields such that graphene can, in principle, be tuned into the Quantum Hall regime. Next, I will discuss the nature of current flow when breaking the inversion symmetry of the system and opening an energy gap [2]. Finally, I will present experimental evidence of hydrodynamic-like flow in this system at alleviated temperatures [3], and a particular electron-phonon thermalization mechanism which is unique to graphene [4].
[1] "Quantum oscillations of the critical current and high-field superconducting proximity
in ballistic graphene”. Nature Physics, 12, 318-U151 (2016)
[2] “Edge currents shunt the insulating bulk in gapped graphene” Nature
communications 8, 14552, (2017)
[3] “Negative local resistance caused by viscous electron backflow in
graphene”. Science 351, 1055-1058, (2016)
[4] "Imaging resonant dissipation from individual atomic defects in graphene" Science
358 (6368), 1303-1306 (2018)