Reentrant topological phases in Mn-doped HgTe quantum wells

TL;DR

This paper investigates reentrant topological phases in Mn-doped HgTe quantum wells, revealing how magnetic doping and external fields induce complex Landau level behaviors and reentrant quantum Hall effects.

Contribution

It introduces a theoretical analysis of reentrant topological phases in Mn-doped HgTe quantum wells considering magnetic doping, well thickness, and temperature effects.

Findings

Reentrant quantum anomalous Hall effect observed due to nonlinear Zeeman effect.

Landau level spectrum exhibits nonmonotonic bending leading to reentrant behavior.

Reentrant phases depend on Mn concentration, well thickness, and temperature.

Abstract

Quantum wells of HgTe doped with Mn display the quantum anomalous Hall effect due to the magnetic moments of the Mn ions. In the presence of a magnetic field, these magnetic moments induce an effective nonlinear Zeeman effect, causing a nonmonotonic bending of the Landau levels. As a consequence, the quantized (spin) Hall conductivity exhibits a reentrant behavior as one increases the magnetic field. Here, we will discuss the appearance of different types of reentrant behavior as a function of Mn concentration, well thickness, and temperature, based on the qualitative form of the Landau-level spectrum in an effective four-band model.