Giant spin rotation under quasiparticle-photoelectron conversion: Joint effect of sublattice interference and spin-orbit coupling

TL;DR

This paper demonstrates that quasiparticle to photoelectron conversion can cause significant spin polarization changes, including total spin flips, due to sublattice interference and spin-orbit coupling, revealing complex spin dynamics in crystals.

Contribution

It introduces a novel mechanism of spin rotation during quasiparticle-photoelectron conversion, highlighting the combined effects of sublattice interference and spin-orbit coupling.

Findings

Quasiparticle spin polarization can undergo dramatic changes during photoemission.

Total spin flips are possible in quasiparticle-photoelectron conversion.

Exotic angular distributions of photoelectrons are observed due to this effect.

Abstract

Spin- and angular-resolved photoemission spectroscopy is a basic experimental tool for unveiling spin polarization of electron eigenstates in crystals. We prove, by using spin-orbit coupled graphene as a model, that photoconversion of a quasiparticle inside a crystal into a photoelectron can be accompanied with a dramatic change in its spin polarization, up to a total spin flip. This phenomenon is typical of quasiparticles residing away from the Brillouin zone center and described by higher rank spinors, and results in exotic patterns in the angular distribution of photoelectrons.