Mass enhancement and electron–hole coupling in InAs/GaSb bilayers studied by cyclotron resonance

We report a study of cyclotron resonance (CR) in a bilayer-bipolar InAs/GaSb structure and the influence of the spatial separation between the electrons and holes. At low magnetic fields we find that the cyclotron mass of the electrons can double when the electrons and holes have a very small separation. At higher cyclotron energies we find that the CR lines are split by a series of resonances which are due to interband coupling, and which also increase rapidly in magnitude when the electron–hole separation is decreased. At very high fields, in the quantum limit a new series of couplings is observed, with the resonances being split by energies in the range of 3–12View the MathML source.