Photon absorption and collective excitations in spintronic superlattices

We calculate the electron density response

function of electron-hole multilayer systems in the presence

of spin-orbit interaction modeled by Rashba terms. It

is found that the spin-orbit coupling leads to a redistribution

of the absorption spectral weight between the particlehole

excitation and the plasmon excitation. The interplay of

Coulomb interactions and spin-orbit interaction resulted in

a suppression or enhancement of the optical absorption due

to plasmons. Our result indicates that the spin-orbit coupling

can serve as a tuning mechanism for optical

absorption in spintronics systems.