Effects of Electron-Electron Scattering in Wide Ballistic Microcontacts

TL;DR

This paper investigates how electron-electron scattering affects the conductance of wide ballistic microcontacts, revealing positive corrections that depend on temperature and are relevant for 2DEG experiments.

Contribution

It provides a theoretical calculation of conductance corrections due to electron-electron interactions in ballistic microcontacts using a semiclassical approach.

Findings

Corrections are positive and scale with T^2 log(E_F/T) in 3D contacts.

Corrections scale linearly with T in 2D contacts.

Results are relevant for interpreting recent 2DEG contact experiments.

Abstract

We calculate the corrections to the Sharvin conductance of ballistic multimode microcontacts that result from electron--electron scattering in the leads. Using a semiclassical Boltzmann equation, we obtain that these corrections are {\it positive} and scale with temperature as $T^2\ln(E_F/T)$ for three-dimensional contacts and as $T$ for two-dimensional ones. These results are relevant to recent experiments on 2DEG contacts.