Topological magnetic textures in magnetic topological insulators

TL;DR

This paper explores the emergence of topological magnetic textures like skyrmions and spin spirals in magnetic topological insulators, highlighting their potential for manipulation via electrostatic gating and applications in spintronics.

Contribution

It introduces a phase diagram of magnetic textures in magnetic TIs based on electron density, revealing skyrmion Wigner crystals and spin spiral phases as new phenomena.

Findings

Skyrmions form in dilute electron regimes, binding to electrons.

Higher electron densities lead to spin spiral phases with chiral channels.

Electron binding to textures suggests potential for electrostatic control.

Abstract

The surfaces of intrinsic magnetic topological insulators (TIs) host magnetic moments exchange-coupled to Dirac electrons. We study the magnetic phases arising from tuning the electron density using variational and exact diagonalization approaches. In the dilute limit, we find that magnetic skrymions are formed which bind to electrons leading to a skyrmion Wigner crystal phase while at higher densities spin spirals accompanied by chiral 1d channels of electrons are formed. The binding of electrons to textures raises the possibility of manipulating textures with electrostatic gating. We determine the phase diagram capturing the competition of intrinsic spin-spin interactions and carrier density and comment on the possible application to experiments in magnetic TIs and spintronic devices such as skyrmion-based memory.