Polaron formation in the presence of Rashba spin-orbit coupling: implications for spintronics

TL;DR

This paper investigates how Rashba spin-orbit coupling influences polaron formation, revealing that increased spin-orbit interaction can reduce effective electron mass and affect spin-polarized current propagation, with implications for spintronics.

Contribution

It introduces a generalized Momentum Average approximation to study the impact of Rashba spin-orbit coupling on polarons, showing it decreases effective electron-phonon coupling and alters polaron spectral properties.

Findings

Spin-orbit coupling reduces the effective electron-phonon interaction.

Increased spin-orbit coupling can lower the polaron effective mass.

Large spin-orbit coupling leads to a single spin-polarized band in the polaron spectrum.

Abstract

We study the effects of the Rashba spin-orbit coupling on the polaron formation, using a suitable generalization of the Momentum Average approximation. Contrary to previous investigations of this problem, we find that the spin-orbit interaction decreases the effective electron-phonon coupling. It is thus possible to lower the effective mass of the polaron by increasing the spin-orbit coupling. We also show that when the spin-orbit coupling is large as compared to the phonon energy, the polaron retains only one of the spin polarized bands in its coherent spectrum. This has major implications for the propagation of spin-polarized currents in such materials, and thus for spintronic applications.