The topological magneto-electric effect (TME) is a characteristic property of topological insulators. In this article, we use a simplified coupled-Dirac-cone electronic structure model to theoretically evaluate the THz and far infrared Kerr and Faraday responses of thin films of MnBi2Te4 with up to N=10 septuple layers with the goal of clarifying the relationship between these convenient magneto-optical observables and the TME. We find that for even N the linear Kerr and Faraday responses to an electric field vanish in the low-frequency limit, even though the magnetoelectric response is large and approximately quantized.
@article{arxiv.2303.14635,
title = {Kerr, Faraday, and Magnetoelectric Effects in MnBi$_2$Te$_4$ Thin Films},
author = {Chao Lei and Allan H. MacDonald},
journal= {arXiv preprint arXiv:2303.14635},
year = {2024}
}