Finite temperature fluctuation-induced order and responses in magnetic topological insulators

Scholten, M. and Facio, J.I. and Ray, R. and Eremin, I.M. and van den Brink, J. and Nogueira, F.S.

Volume: 3 Pages:
DOI: 10.1103/PhysRevResearch.3.L032014
Published: 2021

We derive an effective field theory model for magnetic topological insulators and predict that a magnetic electronic gap persists on the surface for temperatures above the ordering temperature of the bulk. Our analysis also applies to interfaces of heterostructures consisting of a ferromagnetic and a topological insulator. In order to make quantitative predictions for  and for EuS- heterostructures, we combine the effective field theory method with density functional theory and Monte Carlo simulations. For we predict an upwards Néel temperature shift at the surface up to , while the EuS- interface exhibits a smaller relative shift. The effective theory also predicts induced Dzyaloshinskii-Moriya interactions and a topological magnetoelectric effect, both of which feature a finite temperature and chemical potential dependence. © 2021 Published by the American Physical Society

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