Cyclotron resonance of InAs/AlSb single quantum well in high magnetic fields and spin relaxation process

Spin-split cyclotron resonance (CR) of InAs/AlSb single quantum well exhibits a new type hysteresis in strong magnetic fields at low temperature. Pulsed high magnetic fields up to 150 T with a duration of 6 mus were generated by the single turn coil technique. The hysteresis was observed in the up and down sweep process of the fields with B-max greater than or similar to 60 T. This suggests that a non-equilibrium spin-state in the lowest Landau level is induced due to a slow spin reversal rate 1/T-1 approximate to 10(7) s(-1). Two mechanisms for the spin reversal process are proposed: (i) Direct LO-phonon process and (ii) Raman process associated with LO-phonon emission and acoustic phonon absorption. These processes can well explain the characteristic feature of the hysteresis. (C) 2001 Elsevier Science B.V. All rights reserved.