Spin-orbital effects in magnetized quantum wires and spin chains

TL;DR

This paper investigates how magnetic fields and spin-orbit interactions influence quantum wires and spin chains, revealing new magnetic states and proposing ESR as a tool to probe excitations.

Contribution

It uncovers the interplay of Zeeman and spin-orbit effects leading to spin-density waves and analyzes the impact of Dzyaloshinskii-Moriya interactions on magnetic ordering and ESR signals.

Findings

Spin-density wave state emerges with orthogonal magnetic field and spin-orbit axes.

Perpendicular magnetic field induces staggered magnetic order in spin chains.

ESR measurements can distinguish right- and left-moving spin excitations.

Abstract

We present analysis of the interacting quantum wire problem in the presence of magnetic field and spin-orbital interaction. We show that an interesting interplay of Zeeman and spin-orbit terms, facilitated by the electron-electron interaction, results in the spin-density wave (SDW) state when the magnetic field and spin-orbit axes are orthogonal. We show that this instability is enhanced in a closely related problem of Heisenberg spin chain with asymmetric uniform Dzyaloshinskii-Moriya (DM) interaction. Magnetic field in the direction perpendicular to the DM anisotropy axis results in staggered long-range magnetic order along the orthogonal to the applied field direction. We explore consequences of the uniform DM interaction for the electron spin resonance (ESR) measurements, and point out that they provide way to probe right- and left-moving excitations of the spin chain separately.