Theoretical and experimental study of α-Sn deposited on CdTe(001) -: art. no. 115340

Gray tin films enriched by over 95% Sn-119 and grown by molecular beam epitaxy on CdTe(001) wafers are characterized by inelastic nuclear resonance spectroscopy and investigated theoretically by embedded-cluster density-functional theory methods. Experimental tin phonon densities of states are obtained via analysis of resonant scattering of the 23.88-keV nuclear transition, making use of a high-resolution spectrometer at the Advanced Photon Source. Conventional Mossbauer spectroscopy is used in the scattering mode to determine hyperfine parameters of the alpha-Sn phase and, after thermal treatment, the beta phase. Electronic structure in the vicinity of Sn-Cd and Sn-Te interfaces is calculated in order to determine local charge transfer and changes in hyperfine parameters for Sn-119 atoms in the interface region. Although, due to sample thickness, both experiments reveal properties essentially of the bulk, the calculations allow investigation of surface and interface regions at an atomic level, thus providing complementary information. Effects of interlayer relaxation are explored.