Magnetic semiconductor quantum wells in high fields to 60 Tesla: Photoluminescence linewidth annealing at magnetization steps

Magnetic semiconductors offer a unique possibility for strongly tuning the intrinsic alloy disorder potential with applied magnetic field. We report t he direct observation of a series of steplike reductions in the magnetic al loy disorder potential in single ZnSe/Zn(Cd,Mn)Se quantum wells between 0 a nd 60 T. This disorder, measured through the linewidth of low-temperature p hotoluminescence spectra, drops abruptly at similar to 19, 36, and 53 T, in concert with observed magnetization steps. Conventional models of alloy di sorder (developed for nonmagnetic semiconductors) reproduce the general sha pe of the data, but markedly underestimate the size of the linewidth reduct ion. [S0163-1829(99)50328-7].