Luminescence of Cd0.7Mn0.3Te crystals in magnetic field: Linewidth, Landau quantization, and carrier effective mass

Abstract

Cd_0.7Mn_0.3Te crystal photoluminescence is studied in magnetic field up to 7 T in Voigt geometry at 1.6–1.7 K temperature. The range of magnetic field where the approximation of effective band gap narrowing by the s, p – d exchange-interaction-induced term correctly describes experimental results is discussed. Luminescence linewidth (FWHM) broadening due to composition disorder and magnetization fluctuations is evaluated. Functional dependence on magnetic field of magnetic part in broadening, the FWHM(B)_magn., is determined. From the patterns of Landau quantization in luminescence spectra the carrier effective mass value m_e* = 0.104 is calculated and its increase in magnetic field is obtained. Contribution of nonparabolicity and band coupling effects is evaluated in the observed carrier effective mass growth effect.
Keywords: photoluminescence, linewidth (FWHM), effective mass, composition disorder fluctuations, magnetic fluctuations
PACS: 78.20.Ls, 78.55.Et, 05.40.-a