Spin polarization dependence of quasiparticle properties in graphene

TL;DR

This paper investigates how spin polarization affects quasiparticle properties in graphene using a microscopic RPA approach, revealing unique spin-dependent velocity renormalizations and lifetimes relevant for spintronic devices.

Contribution

It provides a detailed quantitative analysis of spin polarization effects on Fermi liquid properties in graphene, highlighting differences from conventional electron liquids.

Findings

Minority-spin velocity renormalization increases at full spin polarization.

Spin dependence of Fermi velocity differs from conventional 2D electron systems.

Majority- to minority-spin lifetime ratio is less than one, depending on polarization and energy.

Abstract

We address spin polarization dependence of graphene's Fermi liquid properties quantitatively using a microscopic Random Phase Approximation theory in an interacting spin-polarized Dirac electron system. We show an enhancement of the minority-spin many-body velocity renormalization at fully spin polarization due to reduction in the electron density and consequently increase in the interaction between electrons near the Fermi surface. We also show that the spin dependence of the Fermi velocity in the chiral Fermi systems is different than that in a conventional two-dimensional electron liquid. In addition, we show that the ratio of the majority- to minority-spin lifetime is smaller than unity and related directly to the polarization and electron energy. The spin-polarization dependence of the carrier Fermi velocity is of significance in various spintronic applications.