Giant Spin-Orbit-Induced Spin Splitting in Bi Chains on GaAs(110)

TL;DR

This study uses first-principles calculations to show that Bi zigzag chains on GaAs(110) surfaces exhibit giant spin splitting due to enhanced spin-orbit coupling and electric dipole interactions, with potential applications in spin transport.

Contribution

It reveals the origin of giant spin splitting in Bi chains on GaAs(110), highlighting the role of asymmetric charge distribution and potential gradients in spintronic properties.

Findings

Bi chains on GaAs(110) show giant spin splitting.

Spin splitting arises from SOC and electric dipole interactions.

Asymmetry of the interface enhances spin splitting.

Abstract

The search for one-dimensional electron systems with a giant Rashba-type spin splitting is of importance for the application of spin transport. Here we report, based on a first-principles density-functional-theory calculation, that Bi zigzag chains formed on a heterogeneous GaAs(110) surface have a giant spin splitting of surface states. This giant spin splitting is revealed to originate from spin-orbit coupling (SOC) and electric dipole interaction that are significantly enhanced by (i) the asymmetric surface charge distribution due to the strong SOC-induced hybridization of the Bi px , py , and pz orbitals and (ii) the large out-of-plane and in-plane potential gradients generated by two geometrically and electronically inequivalent Bi atoms bonding to Ga and As atoms. The results demonstrate an important implication of the in-plane and out-of-plane asymmetry of the Bi/GaAs(110) interface system in producing the giant spin splitting with the in-plane and out-of-plane spin components.