Spin-orbit Interaction in a Dual Gated InAs/GaSb Quantum Well

The spin-orbit interaction is investigated in a dual gated InAs/GaSb quantum well. Using an electric field, the quantum well can be tuned between a single-carrier regime with exclusively electrons as carriers and a two-carrier regime where electrons and holes coexist. The spin-orbit interaction in both regimes manifests itself as a beating in the Shubnikov-de Haas oscillations. In the single-carrier regime the linear Dresselhaus strength is characterized by beta = 28.5 meV angstrom and the Rashba coefficient a is tuned from 75 to 53 meV angstrom by changing the electric field. In the two-carrier regime a quenching of the spin splitting is observed and attributed to a crossing of spin bands.