0.4 and 0.7 conductance anomalies in quantum point contacts

TL;DR

This paper uses self-consistent local spin-density modeling to explain conductance anomalies at 0.4 and 0.7 of the quantum conductance in quantum point contacts, caused by spin-dependent potential splitting at finite temperatures.

Contribution

It introduces a theoretical explanation for conductance anomalies in quantum point contacts without external magnetic fields, based on spin-dependent electrostatic potential splitting.

Findings

Anomalies at 0.4 and 0.7 of conductance quantum are explained by spin effects.

Anomalies persist up to temperatures of 0.5 K.

The model reproduces the simultaneous appearance of both anomalies.

Abstract

Self-consistent modelling based on local spin-density formalism is employed to calculate conductance of quantum point contacts at finite temperatures. The total electrostatic potential exhibits spin-dependent splitting, which persists at temperatures up to 0.5 K and gives rise to the anomalies at 0.4 and 0.7 of the conductance quantum $2e^2/h$ occurring simultaneously in the absence of external magnetic fields.