Geometric Correlations and Breakdown of Mesoscopic Universality in Spin Transport

TL;DR

This paper develops a semiclassical theory for charge and spin transport in mesoscopic systems with spin-orbit interaction, revealing how geometric correlations influence spin conductance and exploring regimes from weak to strong spin-orbit coupling.

Contribution

It introduces a unified semiclassical framework that accounts for geometric correlations affecting spin conductance, extending understanding beyond random matrix theory predictions.

Findings

Spin conductance fluctuates around zero in the absence of geometric correlations.

Geometric correlations induce finite average spin conductance.

The theory is validated by numerical transport calculations across different spin-orbit regimes.

Abstract

We construct a unified semiclassical theory of charge and spin transport in chaotic ballistic and disordered diffusive mesoscopic systems with spin-orbit interaction. Neglecting dynamic effects of spin-orbit interaction, we reproduce the random matrix theory results that the spin conductance fluctuates universally around zero average. Incorporating these effects in the theory, we show that geometric correlations generate finite average spin conductances, but that they do not affect the charge conductance to leading order. The theory, which is confirmed by numerical transport calculations, allows us to investigate the entire range from the weak to the previously unexplored strong spin-orbit regime, where the spin rotation time is shorter than the momentum relaxation time.