Electron-Electron Collisions and a New Hydrodynamic Effect in Two-Dimensional Electron Gas

Some characteristic features of momentum relaxation related to electron-electron collisions in the two-dimensional degenerate electron gas have been analyzed. It has been shown that, along with the Poiseuille flow, a new effect of a hydrodynamic type due to the one-dimensional diffusion of carriers exists in two-dimensional high-mobility wires. It is this effect that seems to be revealed in the experiments reported by Molenkamp and de Jong [Phys. Rev. B 49, 5038 (1994)]. The sensitivity of the new effect to weak magnetic fields may facilitate its experimental identification.