Effect of electron-electron collisions on entrance potential drop in high-mobility 2DEG channels

Usually, the evidence of viscous hydrodynamic transport of frequently colliding conduction electrons is considered to be the “Gurzhi effect,” which requires the scattering of electrons on the channel walls with momentum loss. However, we demonstrate that expansion of Sharvin’s potential drop directly related to frequent electron-electron collisions can be detected even in channels with ideally smooth walls in a two-dimensional degenerate electron gas (2DEG). In theory, this effect could be experimental evidence of the predicted earlier difference between the relaxation times of the antisymmetric and symmetric momentum distributions attributed to the Pauli principle and topological limitations in 2DEG.