Carrier free long-range magnetism in Mo doped one quintuple layer Bi2Te3 and Sb2Te3

TL;DR

This paper predicts that doping Bi2Te3 and Sb2Te3 with molybdenum (Mo) can induce long-range ferromagnetism, potentially enabling quantum anomalous Hall effect in these semiconductors, expanding the scope beyond traditional 3d transition metal dopants.

Contribution

It introduces a novel approach of using 4d transition metal Mo doping to achieve long-range ferromagnetism in topological insulators, which was previously unconfirmed.

Findings

Mo doping induces long-range ferromagnetism in Bi2Te3 and Sb2Te3

Coupling strength comparable to Cr doping in similar systems

Potential for new diluted magnetic semiconductors and QAHE applications

Abstract

One of the keys to the realization of Quantum Anomalous Hall effect (QAHE) is long range ferromagnetism, which is only experimentally realized in Cr or V doped (Bi,Sb)2Te3 system. Both elements are 3d transition metals and 4d transition metals are found to be ineffective to produce long range ferromagnetism in Bi2Se3. Still, whether long range ferromagnetism can be realized by magnetic doping of 4d elements is an open question. Based on density functional theory calculations, we predict that long range ferromagnetism can be realized in Mo doped Bi2Te3 and Sb2Te3, which are semiconducting. The coupling strength is comparable with that of Cr doped Bi2Te3 and Sb2Te3. Therefore, Mo doped Bi2Te3 and Sb2Te3 or their alloys can be new systems to realize diluted magnetic semiconductors and QAHE.