Spin-orbit interaction in InAs/GaSb heterostructures

We investigated spin-orbit interaction (SOI) in InAs/GaSb double quantum wells. A combination of dual-gating and spatially separated electron and hole gases allows for in situ engineering of the band structure. In both the trivial and inverted band alignment regimes, zero-field spin splitting due to SOI was extracted from the beating of the Shubnikov-de Haas oscillations. Deep in the electron regime, we observed anomalous magnetoresistance that points to a highly anisotropic Fermi surface as a result of the intermixing of Dresselhaus and Rashba SOI. In the inverted regime close to the hybridization gap, we obtained an oscillating spin-splitting as a function of electron density, as expected from the band structure calculation.