Ballistic correction to the density of states in an interacting three-dimensional metal

TL;DR

This paper investigates how electron interactions and impurity scattering influence the tunneling density of states in a three-dimensional disordered metal, revealing scale-dependent effects and particle-hole asymmetry.

Contribution

It introduces a ballistic correction to the DOS in 3D metals, highlighting the interplay of interaction and impurity scattering at different spatial scales.

Findings

Large-scale contributions dominate the non-analytic DOS correction.

Small and large scale contributions are comparable, affecting particle-hole symmetry.

The non-analytic DOS part depends only on Fermi surface properties.

Abstract

We study the tunneling density of states (DOS) in an interacting disordered three-dimensional metal and calculate its energy dependence in the quasiballistic regime, for the deviation from the Fermi energy, $E-E_F$, exceeding the elastic scattering rate. In this region, the DOS correction originates from the interplay of the interaction and single-impurity scattering. Depending on the distance between the interaction point and the impurity, one should distinguish (i) the smallest scales of the order of the Fermi wavelength and (ii) larger spatial scales of the order of $\hbar v_F/|E-E_F|$, where $v_F$ is the Fermi velocity. In two dimensions, the large-scale contribution prevails, resulting in a nearly universal DOS correction. The peculiarity of Friedel oscillations in three dimensions is that the contributions from small and large scales are typically comparable, making the DOS correction sensitive to the details of the interaction and demonstrating a significant particle-hole asymmetry. On the other hand, we show that the non-analytic part of the DOS is determined by large scales and can be expressed in terms of the Fermi-surface characteristics only.