Effect of the heterointerface on the spin splitting in modulation doped InxGa1-xAs/InP quantum wells for B→O

Spin splitting of conduction band electrons in In0.53Ga0.47As/In0.77Ga0.23As/InP heterostructures due to spin-orbit coupling is studied by performing Shubnikov-de Haas measurements on nongated and gated Hall bars. From an analysis of the beating pattern in the Shubnikov-de Haas oscillations, the spin-orbit coupling constant is determined. For a symmetric sample no beating pattern and thus no spin splitting is observed. This demonstrates that the k(3) contribution to the spin-orbit coupling constant can be neglected. By applying an envelope function theory it is shown that the major contribution to the Rashba spin-orbit coupling originates from the band offset at the interface of the quantum well. Using gated Hall bar structures it is possible to alter the spin-orbit coupling by application of an appropriate gate voltage. A more negative gate voltage lends to a more pronounced asymmetry of the quantum well, which gives rise to a stronger spin-orbit coupling. (C) 1998 American Institute of Physics.