Spin Texture in Quantum Point Contacts in the Presence of Lateral Spin Orbit Coupling

TL;DR

This paper investigates how lateral spin-orbit coupling affects the conductance and spin textures in quantum point contacts, revealing conductance anomalies linked to spontaneous spin polarization.

Contribution

It introduces a detailed non-equilibrium Green's function analysis of conductance anomalies caused by spin textures in asymmetrically biased QPCs with lateral spin-orbit coupling.

Findings

Conductance anomalies occur below the first quantized plateau.

Anomalies increase with the aspect ratio of the QPC.

Anomalies are signatures of spin textures.

Abstract

A non-equilibrium Green's function formalism is used to study in detail the ballistic conductance of asymmetrically biased side-gated quantum point contacts (QPCs) in the presence of lateral spin-orbit coupling and electron-electron interaction for a wide range of QPC dimensions and gate bias voltage. Various conductance anomalies are predicted below the first quantized conductance plateau (G0=2e2/h) which occur due to spontaneous spin polarization in the narrowest portion of the QPC. The number of observed conductance anomalies increases with increasing aspect ratio (length/width) of the QPC constriction. These anomalies are fingerprints of spin textures in the narrow portion of the QPC.