Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 41: Spinabh
ängiger Transport II

HL 41.3: Vortrag

Donnerstag, 11. März 2004, 15:45–16:00, H17

Influence of magnetic-field induced tuning of disorder and band structure on the magnetoresistance of dilute magnetic semiconductors — •C. Michel, P.J. Klar, S.D. Baranovskii, P. Thomas, and W. Heimbrodt — FB Physik und WZMW, Philipps-Universität, Marburg

We study theoretically the magneto-transport in p-type wide-gap dilute magnetic semiconductors in the paramagnetic phase. Two models (referred to as mobility model and network model) based on a minimal description of the valence band structure and the acceptor state of the DMS are discussed. In both models, band filling effects, magnetic-field splitting of the band states due to the p-d exchange interaction as well as effects of magnetic-field independent disorder are included whereas carrier-carrier interactions other than those responsible for the local magnetism of the Mn ions are neglected. Despite the exclusion of many-body effects in the bands, positive as well as negative MR effects are predicted which show a qualitative agreement with recent experiments on p-type dilute magnetic semiconductors [Ye et al., J. Supercond.: INM 16, 159 (2003), Nam et al., J. Supercond.: INM 16, 335 (2003)]. The differences between the two models arise from a different, model-specific weighting of disorder and occupation effects.