Geometry-assisted topological transitions in spin interferometry

TL;DR

This paper explores how the geometry of mesoscopic interferometers influences topological transitions in spin transport, revealing geometry-specific localization phenomena and their topological interpretation through winding numbers.

Contribution

It demonstrates that the shape of interferometers affects topological spin transitions and introduces a topological framework for understanding these effects in mesoscopic systems.

Findings

Rashba square loops exhibit weak-(anti)localization transitions under in-plane Zeeman fields.

Topological transitions are linked to winding numbers of spin modes.

Geometry-specific effects are absent in Rashba ring loops.

Abstract

We identify a series of topological transitions occurring in electronic spin transport when manipulating spin-guiding fields controlled by the geometric shape of mesoscopic interferometers. They manifest as distinct inversions of the interference pattern in quantum conductance experiments. We establish that Rashba square loops develop weak-(anti)localization transitions (absent in other geometries as Rashba ring loops) as an in-plane Zeeman field is applied. These transitions, boosted by non-adiabatic spin scattering, prove to have a topological interpretation in terms of winding numbers characterizing the structure of spin modes in the Bloch sphere.