Observation of the zero-field spin splitting of the ground electron subband in gasb-inas-gasb quantum wells

A group of GaSb-InAs-GaSb quantum wells with 75- well thickness are studied via magnetotransport. A beating pattern in the Shubnikov-de Haas oscillation is observed. Analysis of the data yields two carrier densities n1=5.1×1011 cm-2 and n1=4.7×1011 cm-2. Both are identified as electrons and are attributed to the population of the ground electron subband whose twofold spin degeneracy is lifted due to the lack of inversion symmetry of the system. A zero-field spin splitting of 3.5 meV is deduced from the electron densities. The evolution of the beating pattern with a tilted magnetic field is also discussed. © 1988 The American Physical Society.