Temperature Induced Spin Density Wave in Magnetic Doped Topological Insulators

TL;DR

This paper investigates how temperature induces a transition from ferromagnetic to spin density wave phases in magnetically doped topological insulators, revealing a novel phase driven by spin susceptibility behavior.

Contribution

It uncovers a temperature-driven phase transition to a spin density wave in doped topological insulators, highlighting the role of spin susceptibility and surface electronic coupling.

Findings

Ferromagnetic order at zero temperature

First order transition to spin density wave with increasing temperature

Coupling between magnetic phases and surface Dirac electrons

Abstract

We study the magnetic properties of topological insulators doped with isoelectronic magnetic impurities. We obtain that at zero temperature the impurities order ferromagnetically, but when raising the temperature the topological insulator undergoes a first order phase transition to a spin density wave phase before the system reaches the paramagnetic phase. The origin of this phase is the non-trivial dependence of the topological insulator spin susceptibility on the momentum. We analyze the coupling of the non-uniform magnetic phase with the Dirac electronic system that occurs at the surfaces of the topological insulators.