Electronic and Magnetic Properties of Ferromagnet-Semiconductor Heterostructure Systems

Abstract

The electronic and magnetic properties of ferromagnet-semiconductor (FM/SC) heterostructure systems have been studied by means of fully relativistic LMTO as well as scalar-relativistic KKR-CPA band structure calculations. As a structural model for our calculations periodic multilayer systems have been assumed, taking for the ferromagnet Fe and for the semiconductor GaAs, respectively. In addition the influence of interdiffusion at the interface was investigated. Concerning the resulting magnetisation profiles the most important features are that no magnetically dead layers occurred and an appreciable induced magnetisation was found in the semiconductor subsystem. To stimulate corresponding experimental work the magnetic circular dichroism has been investigated for the L 2,3 -edges absorption spectra of Ga as well as As. In all cases the circular dichroism was found to be pronounced enough to be detectable. Investigations on the magneto-crystalline anisotropy energy revealed that all of the studied systems should show a perpendicular anisotropy. Calculations of the spin-orbit induced orbital magnetic moment in a spin-resolved way allowed us to check the correlation of this quantity with the magneto-crystalline anisotropy energy. It was found that the relationship suggested recently by van der Laan is quite well fulfilled.