Magnetic Instability on the Surface of Topological Insulators

TL;DR

This paper investigates how electron-electron interactions can induce magnetic instability on the surfaces of 3D topological insulators, revealing a critical interaction strength needed for spontaneous magnetization to occur.

Contribution

It introduces the concept of a critical interaction threshold for magnetic instability on topological insulator surfaces, considering temperature and chemical potential effects.

Findings

Existence of a critical interaction strength for magnetic instability

Surface magnetization depends on temperature and chemical potential

Spontaneous breaking of time reversal symmetry occurs above the threshold

Abstract

Gapless surface states that are protected by time reversal symmetry and charge conservation are among the manifestations of 3D topological insulators. In this work we study how electron-electron interaction may lead to spontaneous breaking of time reversal symmetry on surfaces of such insulators. We find that a critical interaction strength exists, above which the surface is unstable to spontaneous formation of magnetization, and study the dependence of this critical interaction strength on temperature and chemical potential.