Correlated electron current and temperature dependence of the conductance of a quantum point contact

TL;DR

This paper studies how electron-electron interactions at finite temperatures affect the conductance of quantum point contacts, explaining the experimentally observed 0.7 anomaly through a nonlocal kinetic model.

Contribution

It introduces a nonlocal kinetic equation approach to quantify temperature-dependent conductance corrections due to electron interactions near the barrier.

Findings

Negative conductance correction near the 0.7 plateau

Enhanced interaction effects when Fermi level is close to barrier

Agreement with experimental 0.7 conductance feature

Abstract

We investigate finite temperature corrections to the Landauer formula due to electron-electron interaction within the quantum point contact. When the Fermi level is close to the barrier height, the interaction is strongly enhanced due to semiclassical slowing of the electrons. To describe electron transport we formulate and solve a nonlocal kinetic equation for the density matrix of electrons. The correction to the conductance $G$ is negative and strongly enhanced in the region 0.5*2e^2/h < G < 1*2e^2/h . Our results for conductance agree with the so-called ``0.7 structure'' observed in experiments..