Quantum point contact: a case of spin-resolved electron transport

TL;DR

This paper develops a comprehensive theoretical model for spin-resolved electron transport in nano-sized point contacts, unifying different conductance regimes and applying to both magnetic and non-magnetic systems.

Contribution

It introduces a unified approach to describe electrical conductance across diffusive, ballistic, and quantum regimes in spin-resolved nano-contacts.

Findings

Unified model describes contact resistance across multiple regimes

Application to gold nanocontacts and Permalloy nanowires demonstrates versatility

Model captures quantum effects in spin-dependent transport

Abstract

The work presents the extended theoretical model of the electrical conductance in non-magnetic and magnetic nano-size point contacts. The developed approach describes diffusive, quasi-ballistic, ballistic and quantum regimes of the spin-resolved conductance. It is based on the electron transport through metallic junction within approach of the circular constriction. The model provides unified description of the contact resistance from Maxwell diffusive through the ballistic to purely quantum transport regimes without any residual terms depending from the scale. An application are given for experimental treatment of the golden nanocontacts as a non-magnetic case and Permalloy nanowire with/without domain wall as example for the magnetic system. The model of quantum point contact assumes that contact area can be replaced by the quantum object (i.e. magnetic tunnel junction, narrow domain wall, etc.), where potential energy profile determine its electrical properties.