Magnetic Polarons and Other Spin Effects in II-VI Semimagnetic Semiconductors and Their Superlattices.

We review experimental and theoretical aspects of bound magnetic polarons (BMP) in II-VI semimagnetic semiconductors, using the CdTe/Cd sub (1-x) Mn sub x Te system as a prototype. We show how the semiclassical approach of Heiman, Wolff and Warnock [2] can be generalized for magnetic polarons in a quantum well (QW) system. In particular, we calculate the variation of the exciton binding energy in a (111) QW as a function of magnetic field applied perpendicular to the epilayers. Separately, we show how spin fluctuations in this system lead to an enhanced exciton binding via a spin flip induced spin wave exchange between electron and hole, and give the size of the extra binding for x = .25 at T = 2C K.