Quantized topological magnetoelectric effect of the zero-plateau quantum anomalous Hall state

TL;DR

This paper demonstrates that the zero-plateau quantum anomalous Hall state in magnetic topological insulators exhibits a quantized topological magnetoelectric effect, with potential for device applications and elimination of non-topological signals.

Contribution

It proposes realizing the quantized topological magnetoelectric effect in the zero-plateau quantum anomalous Hall state and analyzes finite-size effects numerically.

Findings

Magnetoelectric coefficient converges to a quantized value with increasing film thickness.

Device setup can eliminate non-topological contributions.

Topological magnetoelectric effect is achievable in magnetic topological insulators.

Abstract

Topological magnetoelectric effect in a three-dimensional topological insulator is a novel phenomenon, where an electric field induces a magnetic field in the same direction, with a universal coefficient of proportionality quantized in units of $e^2/2h$. Here we propose that the topological magnetoelectric effect can be realized in the zero-plateau quantum anomalous Hall state of magnetic topological insulators or ferromagnet-topological insulator heterostructure. The finite-size effect is also studied numerically, where the magnetoelectric coefficient is shown to converge to a quantized value when the thickness of topological insulator film increases. We further propose a device setup to eliminate the non-topological contributions from the side surface.