OPTICAL AND MAGNETOTRANSPORT STUDY OF QUATERNARY SEMIMAGNETIC Hg_(1-x-y)Cd_xMn_ySe AND Hg_(1-x-y)Cd_xMn_yTe SINGLE CRYSTALS

摘要

The peculiarities of the exchange interaction between the carrier spin and localized spin moments of magnetic ions in narrow-gap quaternary solid solutions Hg_(1-x-y)Cd_xMn_yTe and Hg_(1-x-y)Cd_xMn_ySe are studied by means of photoluminescence in magnetic field and magneto transport (Shubnikov-de Haas oscillations). It is shown that the s-p hybridization of electron wavefunctions leads to the violation of the conventional selection rules, and the spin-flip processes contribute both in the optical and in the electrical phenomena. The exchange constant α turns out in a complicated function α of energy gap E_g and electron concentration which changes from positive α N_0 = 0.15 eV to negative α N_0 = -0.28 eV values which are typically accepted for wide gap semimagnetic semiconductors.