Quantum Anomalous Hall Effect in Hg$_{1-y}$Mn$_{y}$Te Quantum Wells

TL;DR

This paper predicts the realization of the quantum anomalous Hall effect in Hg$_{1-y}$Mn$_{y}$Te quantum wells driven solely by Mn atom spin polarization, enabling dissipationless charge currents without external magnetic fields.

Contribution

It introduces a theoretical prediction of the quantum anomalous Hall effect in Mn-doped HgTe quantum wells without external magnetic fields, highlighting a new mechanism for dissipationless transport.

Findings

Quantum anomalous Hall effect can occur without external magnetic fields.

The effect depends on quantum well thickness and Mn concentration.

Dissipationless charge current is enabled in spintronics applications.

Abstract

The quantum Hall effect is usually observed when the two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg$_{1-y}$Mn$_{y}$Te quantum wells, without the external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the $Mn$ atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the $Mn$ atoms. This effect enables dissipationless charge current in spintronics devices.