Rashba type spin-orbit splitting of quantum well states in ultrathin Pb films

TL;DR

This paper reports the observation of Rashba-type spin-orbit splitting in quantum well states of ultrathin Pb films on Si(111), revealing unique spin polarization behavior and boundary effects.

Contribution

It demonstrates Rashba spin-orbit splitting in Pb quantum well states and explains the boundary effects causing the observed phenomena.

Findings

Rashba splitting is comparable to semiconductor heterostructures

Splitting shows no coverage dependency

Spin polarization sign is reversed compared to Au(111) surface

Abstract

A Rashba type spin-orbit splitting is found for quantum well states formed in ultrathin Pb films on Si(111). The resulting momentum splitting is comparable to what is found for semiconductor heterostructures. The splitting shows no coverage dependency and the sign of the spin polarization is reversed compared to Rashba splitting in the Au(111) surface state. We explain our results by competing effects at the two boundaries of the Pb layer.