Aharonov-Casher Effect in Wigner Crystal Exchange Interactions

TL;DR

This paper investigates how spin-orbit coupling influences exchange interactions in a low-density Wigner crystal, revealing anisotropic and potentially ferromagnetic exchange effects beyond traditional models.

Contribution

It introduces a theoretical framework showing that spin-orbit coupling induces anisotropic and ferromagnetic exchange interactions in Wigner crystals.

Findings

Exchange interactions can become anisotropic due to spin-orbit coupling.

Two-electron exchange interactions may exhibit ferromagnetic behavior.

Real-space exchange paths forming loops lead to novel interaction effects.

Abstract

We theoretically study the effects of spin-orbit coupling on spin exchange in a low-density Wigner crystal. In addition to the familiar antiferromagnetic Heisenberg exchange, we find general anisotropic interactions in spin space if the exchange paths allowed by the crystal structure form loops in real space. In particular, it is shown that the two-electron exchange interaction can acquire ferromagnetic character.