Charge and spin density response functions of the clean two-dimensional electron gas with Rashba spin-orbit coupling at finite momenta and frequencies

TL;DR

This paper provides exact analytical expressions for charge and spin density response functions in a 2D electron gas with Rashba spin-orbit coupling, analyzing their behavior at finite momenta and frequencies.

Contribution

It derives exact response functions and explores their implications for spin-charge interactions and collective excitations in the system.

Findings

Exact expressions for response functions at finite momenta and frequencies.

Identification of Kohn-like anomalies in spin susceptibilities.

Coupling of charge and spin density modes due to spin-orbit effects.

Abstract

We analytically evaluate charge and spin density response functions of the clean two-dimensional electron gas with Rashba spin-orbit coupling at finite momenta and frequencies. On the basis of our exact expressions we discuss the accuracy of the long-wavelength and the quasiclassical approximations. We also derive the static limit of spin susceptibilities and demonstrate, in particular, how the Kohn-like anomalies in their derivatives are related to the spin-orbit modification of the Ruderman-Kittel-Kasuya-Yosida interaction. Taking into account screening and exchange effects of the Coulomb interaction, we describe the collective charge and spin density excitation modes which appear to be coupled due to nonvanishing spin-charge response function.