Spin-orbit effects on intersubband transitions in quantum wells with two subbands

Thiago S. Mosqueiro, E. Bernardes e J. C. Egues
Instituto de Física de São Carlos (IFSC-USP)

A recently proposed intersubband spin-orbit (s-o) coupling, present in symmetric
two subband quantum wells, can give rise to novel and interesting physical
effects [Phys.Rev.Lett. 99,076603, Phys.Rev.B 78,155313, Phys.Rev.B 80,155314].
Yang, Sweeney and Xu [Phys.Rev.B 50,7474-742] have investigated
optically-induced intersubband transitions in these systems in the absence of
intersubband s-o coupling. Here we extend their work by including the relevant
intersubband s-o interaction. We have also included the Darwin relativistic
correction. In order to properly derive the transition rates, we need to fix the
probability density, including the valence band contribution. We show that the
correct normalization is small, with a quadratic-in-k dependence. Our
preliminary results show that these transition rates strongly depend on the
intersubband coupling, which can be controlled by external fields.

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