Hydrodynamic thermoelectric transport in Corbino geometry

Abstract

We study hydrodynamic electron transport in Corbino graphene devices. Due to the irrotational character of the flow the forces exerted on the electron liquid are expelled from the bulk. We show that in the absence of Galilean invariance force expulsion produces qualitatively new features in thermoelectric transport: i) it results in drops of both voltage and temperature at the system boundaries; ii) in conductance measurements in pristine systems the electric field is not expelled from the bulk. We obtain thermoelectric coefficients of the system in the entire crossover region between charge neutrality and high electron density regime. The thermal conductance exhibits a sensitive Lorentzian dependence on the electron density. The width of the Lorentzian is determined by the fluid viscosity. This enables determination of viscosity of electron liquid near charge neutrality from purely thermal transport measurements. In general, the thermoelectric response is anomalous: it violates the Matthiessen's rule, the Wiedemann-Franz law, and the Mott relation.

Hydrodynamic electron transport in graphene Hall-bar devices

“…The manifestations of hydrodynamic behavior depend sensitively on the device shape and properties of the electron liquid [39,40], which can be accurately tuned in gate-controlled two dimensional devices. For example, the viscous flow of electrons in the Corbino geometry creates discontinuities in voltage and temperature at the sample boundary [41,42], which are caused the force expulsion from the bulk flow.…”