Evidence for local spots of viscous electron flow in graphene at moderate mobility

Abstract

Dominating electron-electron scattering enables viscous electron flow exhibiting hydrodynamic current density patterns such as Poiseuille profiles or vortices. The viscous regime has recently been observed in graphene by non-local transport experiments and mapping of Poiseuille profiles up to room temperature. Here, we probe the currentinduced surface potential maps of graphene field effect transistors using scanning probe microscopy at room temperature. We discover the appearance of µm large areas close to charge neutrality, where the current induced electric field opposes the externally applied field. By estimating the scattering lengths from the gate dependence of local 1

Anomalous Gurzhi effect

“…The realization of the hydrodynamic regime in graphene [20][21][22][23][24][25][26][27][28] had a strong impact on the development of electron hydrodynamics in solids [29,30]. Recently, signatures of the electron hydrodynamics were also observed in three-dimensional (3D) Dirac and Weyl semimetals.…”