Persistent spin currents in electron systems with spin-orbit interaction

TL;DR

This paper explores the existence and robustness of persistent spin currents in electron systems with spin-orbit interaction, linking topological properties to potential for stable spin transport at zero temperature.

Contribution

It demonstrates that nontrivial topology in electron configuration spaces enables persistent spin currents that are resistant to impurity scattering, addressing a challenge posed by Rashba.

Findings

Persistent spin currents are linked to Berry phases and topological invariants.

Nontrivial topology allows for nonzero, stable spin currents in ideal conditions.

Realization of background spin currents in finite systems confirms theoretical predictions.

Abstract

We investigate the persistent spin currents in one- and two-dimensional electron systems with spin-orbit interaction in thermodynamics equilibrium at absolute zero temperature. The persistent spin current is the intrinsic one which is connected with the Berry phases in the configuration spaces of an electron system and winding numbers in the field configurations of electrons. When the topological space of the configuration of a system has the nontrivial first homotopy groups, the persistent spin currents in the system could be nonzero and not easily destroyed by impurity scattering in ballistic limit. The non-vanishing background spin currents in infinite two-dimensional electron system found by Rashba could be realized by the transport persistent spin currents in a finite torus electron system with spin-orbit interaction. In this sense, we meet the challenge proposed by Rashba.