Electric field effect on electron gas spins in two-dimensional magnets with strong spin-orbit coupling

TL;DR

This paper investigates how electric fields influence electron spin textures in two-dimensional magnetic materials with strong spin-orbit coupling, revealing mechanisms for spin tilting, skyrmion formation, and resonant spin dynamics.

Contribution

It provides a unified microscopic theory of electron gas spin responses to electric perturbations, highlighting the roles of potential inhomogeneity and Berry curvature effects.

Findings

Electrostatic potential inhomogeneity induces spin tilting and skyrmion-like textures.

Oscillating electric fields can cause resonant spin precession and electric dipole spin resonance.

Static and dynamic spin phenomena are linked to the electronic band Berry curvature.

Abstract

The recent rise of material platforms combining magnetism and two-dimensionality of mobile carriers reveals a diverse spectrum of spin-orbit phenomena and stimulates its ongoing theoretical discussions. In this work we use the density matrix approach to provide a unified description of subtle microscopic effects governing the electron gas spin behavior in the clean limit upon electric perturbations in two-dimensional magnets with strong spin-orbit coupling. We discuss that an inhomogeneity of electrostatic potential generally leads to the electron gas spin tilting with the subsequent formation of equilibrium skyrmion-like spin textures and demonstrate that several microscopic mechanisms of 2DEG spin response are equally important for this effect. We analyze the dynamics of 2DEG spin upon an oscillating electric field with a specific focus on the emergent electric dipole spin resonance. We address the resonant enhancement of magneto-optical phenomena from the spin precession equation perspective and discuss it in terms of the resonant spin generation. We also clarify the connection of both static and dynamic spin phenomena arising in response to a scalar perturbation with the electronic band Berry curvature.