Effects of two dimensional plasmons on the tunneling density of states

Abstract

We show that gapless plasmons lead to a universal $(\delta\nu(\epsilon)/\nu\propto |\epsilon|/E_F)$ correction to the tunneling density of states of a clean two dimensional Coulomb interacting electron gas. We also discuss a counterpart of this effect in the "composite fermion metal" which forms in the presence of a quantizing perpendicular magnetic field corresponding to the half-filled Landau level. We argue that the latter phenomenon might be relevant for deviations from a simple scaling observed by A.Chang et al in the tunneling $I-V$ characteristics of Quantum Hall liquids.