Silicon surface with giant spin-splitting

TL;DR

This paper reports the discovery of a giant Rashba-type spin-splitting on a silicon surface induced by a bismuth adlayer, with potential implications for spintronics and semiconductor technology.

Contribution

It demonstrates a significantly larger spin-splitting on silicon than previously reported, confirmed by experiments and first-principles calculations.

Findings

Giant Rashba spin-splitting of about 140 meV observed.

Separation of electronic states exceeds their lifetime broadening.

Experimental results confirmed by relativistic first-principles calculations.

Abstract

We demonstrate the induction of a giant Rashba-type spin-splitting on a semiconducting substrate by means of a Bi trimer adlayer on a Si(111) wafer. The in-plane inversion symmetry is broken so that the in-plane potential gradient induces a giant spin-splitting with a Rashba energy of about 140 meV, which is more than an order of magnitude larger than what has previously been reported for any semiconductor heterostructure. The separation of the electronic states is larger than their lifetime broadening, which has been directly observed with angular resolved photoemission spectroscopy. The experimental results are confirmed by relativistic first-principles calculations. We envision important implications for basic phenomena as well as for the semiconductor based technology.