Resonant electron spin-flip Raman scattering in CdTe and the diluted magnetic semiconductor Cd_1-xV_xTe

Abstract

Resonant enhancement enables the discovery and delineation of spin-flip Raman scattering (SFRS) from free or donor-bound electrons in diluted magnetic semiconductors containing 3d transition-metal ions at doping concentrations. In such studies, the intrinsic g factor of the host, CdTe in the present case, has to be accounted for accurately. The SFRS in CdTe yields the conduction band electron g factor of -1.676± 0.007 and displays two resonance peaks mediated by free and donor-bound excitons, respectively. Excitonic signature in modulated reflectivity signals the successful formation of Cd_1-xV_xTe as an alloy, whereas magnetization measurements show vanadium ions incorporated as V²⁺ with x∼4×10^-4. SFRS of Cd_1-xV_xTe displays vanadium related SFRS shifts of a sign opposite to that of the host. This indicates a ferromagnetic s-d exchange interaction between the s-like conduction electrons and the 3d shell of V²⁺ in Cd_1-xV_xTe; from the linear dependence of the s-d exchange energy as a function of magnetization α N₀, the s-d exchange constant is deduced to be 285± 8meV.