Rashba-like spin splitting along three momentum directions in trigonal layered PtBi2

TL;DR

This paper reports the discovery of giant, anisotropic 3D Rashba-like spin splitting with helical spin polarization in trigonal layered PtBi2, advancing the understanding of spin-orbit coupling effects for spintronics.

Contribution

It reveals a novel 3D Rashba-like spin splitting in PtBi2 caused by combined Rashba and Dresselhaus SOC, which was not previously observed in this material class.

Findings

Giant anisotropic 3D Rashba-like spin splitting observed

Helical spin polarization around M points in Brillouin zone

Spin splitting characterized by alpha~ 4.36 eVA

Abstract

Spin-orbit coupling (SOC) has gained much attention for its rich physical phenomena and highly promising applications in spintronic devices. The Rashba-type SOC in systems with inversion symmetry breaking is particularly attractive for spintronics applications since it allows for flexible manipulation of spin current by external electric fields. Here, we report the discovery of a giant anisotropic Rashba-like spin splitting along three momentum directions (3D Rashba-like spin splitting) with a helical spin polarization around the M points in the Brillouin zone of trigonal layered PtBi2. Due to its inversion asymmetry and reduced symmetry at the M point, Rashba-type as well as Dresselhaus-type SOC cooperatively yield a 3D spin splitting with alpha~ 4.36 eVA in PtBi2. The experimental realization of 3D Rashba-like spin splitting not only has fundamental interests but also paves the way to the future exploration of a new class of material with unprecedented functionalities for spintronics applications.