Superexchange in AIIBVI Diluted Magnetic Semiconductors with Mn, Fe and Co Ions
J. Blinowski
Institute of Theoretical Physics, Warsaw University, Hoża 69, 00-681 Warszawa, Poland

and P. Kacman
Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa, Poland
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A theory of superexchange, the dominant ion-ion spin interaction, for Mn-, Fe- and Co-based DMS is presented. The theory takes into account the band structure of AIIBVI compounds, the orbital dependence of the hybridization and the intra shell correlations of the d-electrons, which are essential in the case of the non-S-state ions. The general formulae relating the superexchange to the band structure and the ionic energy spectrum were obtained - the dominant part of the superexchange turns out to be inversely proportional to the square of the ionic spin. This explains the observed in­crease in the average values of d-d exchange constants, when passing from Mn via Fe to Co ions in DMS.
DOI: 10.12693/APhysPolA.87.539
PACS numbers: 75.50.Pp, 75.30.-m