Impact of Dresselhaus vs. Rashba spin-orbit coupling on the Holstein polaron

TL;DR

This study investigates how Dresselhaus and Rashba spin-orbit couplings influence polaron properties, revealing tunable effective mass and density of states modifications through numerical analysis.

Contribution

It provides a detailed numerical analysis of the impact of combined Dresselhaus and Rashba couplings on polaron ground state properties, highlighting tunability of effective mass.

Findings

Van-Hove singularity shifts and disappears when couplings are equal

Effective mass is suppressed, especially at low phonon frequencies

Dual spin-orbit couplings allow for varied tuning of polaron characteristics

Abstract

We utilize an exact variational numerical procedure to calculate the ground state properties of a polaron in the presence of Rashba and linear Dresselhaus spin-orbit coupling. We find that when the linear Dresselhaus spin-orbit coupling approaches the Rashba spin-orbit coupling, the Van-Hove singularity in the density of states will be shifted away from the bottom of the band and finally disappear when the two spin-orbit couplings are tuned to be equal. The effective mass will be suppressed; the trend will become more significant for low phonon frequency. The presence of two dominant spin-orbit couplings will make it possible to tune the effective mass with more varied observables.