Abstract:

Spin-orbit coupling in condensed matter physics comes in many different forms. In solids with a center of inversion, the coupling manifests itself as an additional (to Kramers) degeneracy, with spin-modulated Bloch states. In systems lacking spatial inversion, the coupling appears as an effective, momentum dependent magnetic field. Most prominent examples are the Dresselhaus and Bychkov-Rashna spin-orbit Hamiltonians in zinc-blende heterostructures. What happens at metal/semiconductor interfaces is virtually unknown. We have performed ab initio calculations for the important case of Fe/GaAs interface to show that the usual Dresselhaus and Bychkov-Rashba description are valid also here, close to the k=0 point, while at larger momenta the spin-orbit coupling fields assume more exotic forms. Theoretical background as well as experimental ramifications of the discovered spin-orbit fields will be discussed.
 
 
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