Ubiquitous Ideal Spin-Orbit Coupling in a Screw Dislocation in Semiconductors

TL;DR

This paper theoretically reveals that screw dislocations in semiconductors induce a universal, highly coherent 1D spin-orbit coupling effect that can be tuned to suppress spin relaxation, offering new avenues for spin transport manipulation.

Contribution

It introduces a novel form of spin-orbit coupling associated with screw dislocations, distinct from traditional surface/interface effects, and demonstrates its tunability in semiconductors.

Findings

SD-SOC exhibits higher spin coherency than 2D RD-SOC.

SD-SOC can be tuned by ionicity to suppress spin relaxation.

First-principles calculations confirm the presence of SD-SOC in various semiconductors.

Abstract

We theoretically demonstrate that screw dislocation (SD), a 1D topological defect widely present in semiconductors, exhibits ubiquitously a new form of spin-orbit coupling (SOC) effect. Differing from the widely known conventional 2D Rashba-Dresselhaus (RD) SOC effect that typically exists at surfaces/interfaces, the deep-level nature of SD-SOC states in semiconductors readily makes it an ideal SOC. Remarkably, the spin texture of 1D SD-SOC, pertaining to the inherent symmetry of SD, exhibits a significantly higher degree of spin coherency than the 2D RD-SOC. Moreover, the 1D SD-SOC can be tuned by ionicity in compound semiconductors to ideally suppress spin relaxation, as demonstrated by comparative first-principles calculations of SDs in Si/Ge, GaAs, and SiC. Our findings therefore open a new door to manipulating spin transport in semiconductors by taking advantage of an otherwise detrimental topological defect.