Regensburg 2019 – wissenschaftliches Programm
SYHE 1.5: Hauptvortrag
Mittwoch, 3. April 2019, 11:45–12:15, H1
Electron hydrodynamics in graphene: introduction and status — •Denis Bandurin — Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
Transport in systems with many particles experiencing frequent collisions has been studied for more than two centuries and is accurately described by the theory of hydrodynamics. It has been argued theoretically for a long time that the collective behaviour of charge carriers in solids can also be treated by the hydrodynamic approach. However, despite numerous attempts, very little evidence of hydrodynamic electron transport has been found.
Graphene encapsulated between hexagonal boron nitride offers an ideal platform to study electron hydrodynamics as it hosts an ultra-clean electronic system with electron-electron collisions being the dominant scattering source at elevated temperatures. In the first part of my talk, we will discuss why it was challenging to detect electron hydrodynamics before and how it manifests itself in graphene. It will be shown that electrons in graphene can behave as a viscous fluid forming vortices of applied electron current. In the second part, we will talk about the behaviour of electron fluids in the presence of magnetic field where I will report the experimental measurements of the odd (Hall) viscosity. This dissipationless transport coefficient has been widely discussed in the theoretical literature on fluid mechanics, yet, until now, any experimental evidence has been lacking. Finally, we will discuss how electron hydrodynamics can help in the development of resonant THz detectors where I will report some recent progress in this direction.