Quasi-two-dimensional carriers in dilute-magnetic-semiconductor quantum wells under in-plane magnetic field

摘要

Due to the competition between spatial and magnetic confinement, the density of states (DOS) of a quasi-two-dimensional system deviates from the ideal step-like form both quantitatively and qualitatively. We study how this affects the spin-subband populations and the spin polarization as functions of the temperature, T, and the in-plane magnetic field, B, for narrow to wide dilute-magnetic-semiconductor quantum wells (QWs). We focus on the QW width, the magnitude of the spin-spin exchange interaction, and the sheet carrier concentration dependence. We look for ranges where the system is completely spin polarized. Increasing T, the carrier spin splitting, U-0 sigma, decreases, while on increasing B, U-0 sigma increases. Moreover, due to the DOS modification, all energetically higher subbands become gradually depopulated. (C) 2007 Elsevier B.V. All rights reserved.