Parallel spin-momentum locking in a chiral topological semimetal
Abstract
Spin-momentum locking in solids describes a directional relationship between the electron's spin angular momentum and its linear momentum over the entire Fermi surface. While orthogonal spin-momentum locking, such as Rashba spin-orbit coupling, has been studied for decades and inspired a vast number of applications, its natural counterpart, the purely parallel spin-momentum locking, has remained elusive in experiments. Recently, chiral topological semimetals that host single- and multifold band crossings have been predicted to realize such parallel locking. Here, we use spin- and angle-resolved photoelectron spectroscopy to probe spin-momentum locking of a multifold fermion in the chiral topological semimetal PtGa via the spin-texture of its topological Fermi-arc surface states. We find that the electron spin of the Fermi-arcs points orthogonal to their Fermi surface contour for momenta close to the projection of the bulk multifold fermion, which is consistent with parallel spin-momentum locking of the latter. We anticipate that our discovery of parallel spin-momentum locking of multifold fermions will lead to the integration of chiral topological semimetals in novel spintronic devices, and the search for spin-dependent superconducting and magnetic instabilities in these materials.
Cite
@article{arxiv.2210.08221,
title = {Parallel spin-momentum locking in a chiral topological semimetal},
author = {Jonas A. Krieger and Samuel Stolz and Inigo Robredo and Kaustuv Manna and Emily C. McFarlane and Mihir Date and Eduardo B. Guedes and J. Hugo Dil and Chandra Shekhar and Horst Borrmann and Qun Yang and Mao Lin and Vladimir N. Strocov and Marco Caputo and Banabir Pal and Matthew D. Watson and Timur K. Kim and Cephise Cacho and Federico Mazzola and Jun Fujii and Ivana Vobornik and Stuart S. P. Parkin and Barry Bradlyn and Claudia Felser and Maia G. Vergniory and Niels B. M. Schröter},
journal= {arXiv preprint arXiv:2210.08221},
year = {2024}
}