Speaker
Description
We study hydrodynamic electron transport in Corbino and Hall bar graphene devices. In Corbino geometry 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 and (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 the 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. For Hall bar devices subject to long-range inhomogeneities we show that the effective electrical conductivity of the system may significantly exceed the intrinsic conductivity of the electron liquid.
