Spin Polarization of Photoelectrons from Topological Insulators

TL;DR

This paper demonstrates that photoelectrons emitted from topological insulators can achieve complete spin polarization under certain conditions, with their spin orientation controllable by photon polarization, revealing new phenomena confirmed experimentally.

Contribution

It reveals that photoelectrons from topological insulators can have 100% spin polarization and their spin orientation can be manipulated via photon polarization, advancing understanding of spin dynamics.

Findings

Photoelectrons can be fully spin-polarized (100%) with polarized light.

Spin orientation of photoelectrons can be controlled by photon polarization.

Experimental confirmation of predicted phenomena.

Abstract

We show that the degree of spin polarization of photoelectrons from the surface states of topological insulators is 100% if fully-polarized light is used as in typical photoemission measurements, and hence can be significantly "higher" than that of the initial state. Further, the spin orientation of these photoelectrons in general can also be very different from that of the initial surface state and is controlled by the photon polarization; a rich set of predicted phenomena have recently been confirmed by spin- and angle-resolved photoemission experiments.