Observation of Electronic Viscous Dissipation in Graphene Magneto-thermal Transport

by Dr. Jonah Waissman

The Institute of Applied Physics, HUJI

at Condensed Matter Seminar

Mon, 24 Jun 2024, 11:10
Sacta-Rashi Building for Physics (54), room 207

Abstract

Hydrodynamic transport effectively describes the collective dynamics of fluids with well-defined thermodynamic quantities. With enhanced electron-electron
interactions at elevated temperatures, the collective behavior of electrons in graphene with minimal impurities can be depicted as a
hydrodynamic flow of charges. In this new regime, the well-known rules of Ohmic transport based on a single-electron picture
no longer apply, necessitating the consideration of collective electron dynamics. In particular, the hydrodynamic analogues of Joule heat-
ing and thermal transport require consideration of the viscous motion of the electron fluid, which has a direct impact on the energy dissi-
pation and heat generation by the fluidic motion of charge. In this work, we probe graphene hydrodynamics with thermal transport and
find two distinct, qualitative signatures: thermal conductivity suppression below the Wiedemann-Franz value and viscous heating leading
to magnetically-induced redistribution of temperature. We find these two effects are coincident in temperature and density, providing robust
qualitative signatures of hydrodynamics, despite arising from two distinct aspects of this new regime: microscopic momentum conservation
due to electron-electron scattering, and geometry-dependent viscous dissipation. Our results mark the first observation of viscous electronic
heating in an electron fluid, providing insight for optimizing thermal management in electronic hydrodynamic devices and offering a new
methodology for identifying hydrodynamic states in other systems.

Created on 19-06-2024 by Naamneh, Muntaser (mnaamneh)
Updaded on 19-06-2024 by Naamneh, Muntaser (mnaamneh)