The Spin Mass of an Electron Liquid

TL;DR

This paper introduces the concept of an effective 'spin mass' $m_s$ for quasiparticles in an electron liquid, which is crucial for accurately calculating spin currents and differs from other effective masses, with significant enhancement effects shown.

Contribution

It presents the first microscopic calculations of the spin mass $m_s$ in 2D and 3D electron liquids, highlighting its importance for spin transport.

Findings

The spin mass $m_s$ can be significantly larger than the band and quasiparticle effective masses.

Microscopic calculations show substantial mass enhancement $m_s/m_b$ in electron liquids.

The results impact understanding of spin current behavior in electron systems.

Abstract

We show that in order to calculate correctly the {\it spin current} carried by a quasiparticle in an electron liquid one must use an effective "spin mass" $m_s$, that is larger than both the band mass, $m_b$, which determines the charge current, and the quasiparticle effective mass $m^*$, which determines the heat capacity. We present microscopic calculations of $m_s$ in a paramagnetic electron liquid in three and two dimensions, showing that the mass enhancement $m_s/m_b$ can be a very significant effect.