Characterization of In_1-xMn_xAs/GaSb Quantum Wells by Shubnikov de Haas Oscillations and Cyclotron Resonance

The InAs/GaSb broken gap III-V heterojunctions can host a two-dimensional quantum spin Hall state resulting from a band-inverted electronic structure. At the interface between the two materials, the InAs conduction band edge lies below the GaSb valence band edge. The hybridization of these levels cause a topological gap to open. The observation of the quantum anomalous Hall effect (QAHE) is expected to occur if the s-p ordering is inverted (non-trivial) for one spin species and trivial for the other, which can be achieved through the introduction of Mn into system. In this work, we characterize a series of Mn doped InAs/GaSb type-II quantum wells. Robust SdH oscillations and Hall quantization between 1.5K and 50K are observed in magneto-transport. We perform magneto-optics up to 15T to measure the cyclotron mass. We find that at high Mn content, InMnAs/GaSb samples are p-type, while at intermediate content, they host a coexisting 2DEG and hole channel that can either be due to band bending or a Mn impurity level. We hypothesize that Mn can serve both as a source of magnetic exchange and Fermi level pinning in InAs/GaSb.