Effective g-factor and phase-coherent transport in InAsSb/InSb double quantum wells*

High-quality semiconductor structures with large Landé g-factors are a cornerstone of many fundamental applications in spintronics and quantum information processing with topological qubits. Here, we propose the InAsSb/InSb double quantum wells (DQWs), grown by molecular-beam epitaxy (MBE) on a virtual substrate, as such a material system, with additional advantages of tunable bandgaps and the possibility of tuning the band topology. Specifically, using the tilted magnetic field method, we show that the in-plane electron g-factor in InAsSb/InSb DQWs is large (> 20), which we deduce from the coincidence of the spin levels of adjacent Landau levels. We further study the phase-coherent transport in InAsSb/InSb DQWs from weak anti-localization measurements and conclude that the dominant decoherence mechanism in our samples is electron-electron scattering.