MAGNETOOPTICAL STUDY OF GA(1-X)IN(X)SB GASB STRAINED-QUANTUM-WELL STRUCTURES - MINIBAND FORMATION AND VALENCE-BAND STRUCTURE/

Interband magneto-optical studies have been performed on a series of s trained single and coupled Ga1-xInxSb/GaSb quantum wells. We have inve stigated the dependence of interwell coupling on the well and barrier thicknesses and on the In content of the wells. Superlattice miniband formation is discussed where we observe a large anisotropy in carrier masses along and perpendicular to the, growth direction. A reduced in- plane mass of the highest valence band (\m(J)\ = 3/2, conventional hea vy-hole band) is observed, dependent on the degree of the heavy-hole-l ight-hole (\m(J)\ = 1/2) decoupling. An extra Landau level transition appears between the conventional l = 0 and l = 1 Landau level transiti ons, increasing in intensity as the magnetic field perpendicular to th e layer increases. This is interpreted as a result of mixing between t he heavy-hole and light-hole states induced by the magnetic field. Int erband spin splitting is observed in narrow Ga0.88In0.12Sb/GaSb single quantum wells but not wide wells. The difference arises from the vale nce-band spin splittings, which are very dependent on the heavy-hole-l ight-hole coupling, and therefore on the quantum-well width. These las t two observations are explained well by Landau level calculations wit h the Luttinger k.p Hamiltonian.