Temperature dependent spin susceptibility in a two-dimensional metal

TL;DR

This paper demonstrates that in a two-dimensional electron system with Coulomb interactions, the spin susceptibility exhibits a linear temperature dependence due to the dynamic Kohn anomaly, aligning with Landau theory predictions.

Contribution

It reveals that Coulomb interactions induce a non-analytic correction to spin susceptibility at finite temperature, extending understanding of Fermi liquid behavior in 2D systems.

Findings

Linear-in-T correction to spin susceptibility due to Kohn anomaly

Coulomb interaction's non-analyticity does not invalidate r_s expansion

Consistency with Landau theory's non-analytic Landau function

Abstract

We consider a two-dimensional electron system with Coulomb interaction between particles at a finite temperature T. We show that the dynamic Kohn anomaly in the response function at 2K_F leads to a linear-in-T correction to the spin susceptibility, same as in systems with short-range interaction. We show that the singularity of the Coulomb interaction at q=0 does not invalidate the expansion in powers of r_s, but makes the expansion non-analytic. We argue that the linear temperature dependence is consistent with the general structure of Landau theory and can be viewed as originating from the non-analytic component of the Landau function near the Fermi surface.