Giant Rashba-type spin splitting through spin-dependent interatomic-hopping

TL;DR

This paper reveals that giant Rashba-type spin splitting in Bi/Ag(111) is primarily driven by spin-dependent interatomic hopping rather than electric fields, offering new insights for designing spintronic materials.

Contribution

It introduces a novel mechanism where spin-dependent hopping energy causes giant RSS, shifting focus from electric fields to atomic-scale interactions.

Findings

Spin-dependent hopping induces large RSS in Bi/Ag(111).

Effective field from hopping energy difference is approximately 18 V/Å.

New strategy for designing RSS materials by controlling hopping energy.

Abstract

We have performed density functional theory calculation and tight binging analysis in order to investigate the mechanism for the giant Rashba-type spin splitting (RSS) observed in Bi/Ag(111). We find that local orbital angular momentum induces momentum and spin dependent charge distribution which results in spin-dependent hopping. We show that the spin-dependent interatomic-hopping in Bi/Ag(111) works as a strong effective field and induces the giant RSS, indicating that the giant RSS is driven by hopping, not by a uniform electric field. The effective field from the hopping energy difference amounts to be ~18 V/{\AA}. This new perspective on the RSS gives us a hint for the giant RSS mechanism in general and should provide a strategy for designing new RSS materials by controlling spin-dependence of hopping energy between the neighboring atomic layers.