Electric-field control of magnetic anisotropies: applications to Kitaev spin liquids and topological spin textures

TL;DR

This paper develops a microscopic theory showing how DC electric fields can control magnetic anisotropies, induce topological phase transitions, and manipulate spin textures in Kitaev materials and related systems.

Contribution

It introduces a microscopic approach based on Hubbard-like models to explain electric-field effects on magnetic interactions and topological spin textures in strongly spin-orbit coupled materials.

Findings

Electric fields induce non-Kitaev interactions like Dzyaloshinskii-Moriya and Gamma' terms.

Electric fields can drive topological quantum phase transitions between Majorana phases.

Magnetic skyrmions and other topological textures can be created and annihilated by electric fields.

Abstract

Magnetic anisotropies often originate from the spin-orbit coupling and determine magnetic ordering patterns. We develop a microscopic theory for DC electric-field controls of magnetic anisotropies in magnetic Mott insulators and discuss its applications to Kitaev materials and topological spin textures. Throughout this paper, we take a microscopic approach based on Hubbard-like lattice models, tight-binding models with on-site interactions. We derive a low-energy spin Hamiltonian from a fourth-order perturbation expansion of the Hubbard-like model. We show in the presence of a strong intra-atomic spin-orbit coupling that DC electric fields add non-Kitaev interactions such as a Dzyaloshinskii-Moriya interaction and an off-diagonal $\Gamma'$ interaction to the Kitaev-Heisenberg model and can induce a topological quantum phase transition between Majorana Chern insulating phases. We also investigate the inter-atomic Rashba spin-orbit coupling and its effects on topological spin textures. DC electric fields turn out to create and annihilate magnetic skyrmions, hedgehogs, and chiral solitons. We propose several methods of creating topological spin textures with external electromagnetic fields. Our theory clarifies that the strong but feasible electric field can control Kitaev spin liquids and topological spin textures.