Local moment formation in quantum point contacts

TL;DR

This paper uses spin-density-functional theory to demonstrate the formation of a local magnetic moment near quantum point contacts, supporting the existence of a Kondo effect and analyzing how the contact length affects hybridization.

Contribution

It provides a theoretical demonstration of local moment formation in QPCs and explores how contact length influences the Kondo effect.

Findings

Local moment with one electron spin forms near QPCs

Hybridization decreases as QPC lengthens

Onsite Coulomb energy remains nearly constant

Abstract

Spin-density-functional theory of quantum point contacts (QPCs) reveals the formation of a local moment with a net of one electron spin in the vicinity of the point contact - supporting the recent report of a Kondo effect in a QPC. The hybridization of the local moment to the leads decreases as the QPC becomes longer, while the onsite Coulomb-interaction energy remains almost constant.