Quantum Anomalous Hall Effect in Magnetically Doped InAs/GaSb Quantum Wells

Abstract

The quantum anomalous Hall effect has recently been observed experimentally in thin films of Cr doped (Bi,Sb)2Te3 at a low temperature (∼ 30mK). In this work, we propose realizing the quantum anomalous Hall effect in more conventional diluted magnetic semiconductors with doped InAs/GaSb type II quantum wells. Based on a four band model, we find an enhancement of the Curie temperature of ferromagnetism due to band edge singularities in the inverted regime of InAs/GaSb quantum wells. Below the Curie temperature, the quantum anomalous Hall effect is confirmed by the direct calculation of Hall conductance. The parameter regime for the quantum anomalous Hall phase is identified based on the eight-band Kane model. The high sample quality and strong exchange coupling make magnetically doped InAs/GaSb quantum wells good candidates for realizing the quantum anomalous Hall insulator at a high temperature.

Quantum anomalous Hall effect in graphene coupled to skyrmions

“…Interestingly, we find that this system can exhibit the quantum anomalous Hall effect [Figs. 1(e) and 1(f)], a topological phase of matter that is being actively pursued in condensed-matter physics [22].…”

Quantum anomalous Hall effect in time-reversal-symmetry breaking topological insulators

“…12 Alternatively, another 2D TI, InAs/GaSb quantum wells with magnetic doping was also predicted to be a QAH insulator [30]. There are many advantages in this system compared to Mn-doped HgTe.…”

“…There are many advantages in this system compared to Mn-doped HgTe. First and foremost, the FM Curie temperature (T C ) in this system can be significantly enhanced due to the nontrivial band structures [30]. Secondly, high-quality (In,Mn)As/GaSb heterostructure have been successfully fabricated by molecular beam epitaxy (MBE) [31].…”

Quantum Anomalous Hall Effect

“…Moreover, different behaviors between exchange coupling of magnetic moments and the orbital effect from magnetic fields can also be unveiled by rotating magnetic fields [41]. More recently, it was proposed that the QAH effect can be realized in another diluted magnetic semiconductor heterostructure, Mn doped type II InAs/GaSb quantum wells [42]. Both InAs and GaSb are III-V group semiconductors.…”