Crystal-symmetry-paired spin-valley locking in a layered room-temperature antiferromagnet

TL;DR

This paper reports the discovery of a layered room-temperature antiferromagnet exhibiting crystal-symmetry-paired spin-valley locking, demonstrating unique spin properties and potential for spintronic applications, confirmed through experimental and theoretical methods.

Contribution

It presents the first experimental realization of C-paired spin-valley locking in a layered antiferromagnet, combining layered material advantages with unconventional spin properties.

Findings

Direct spin-resolved photoemission evidence of opposite spin splitting in valleys.

Suppression of inter-valley scattering due to spin selection rules.

Experimental results align with first-principles calculations.

Abstract

Recent theoretical efforts predicted a type of unconventional antiferromagnet characterized by the crystal symmetry C (rotation or mirror), which connects antiferromagnetic sublattices in real space and simultaneously couples spin and momentum in reciprocal space. This results in a unique C-paired spin-valley locking (SVL) and corresponding novel properties such as piezomagnetism and noncollinear spin current even without spin-orbit coupling. However, the unconventional antiferromagnets reported thus far are not layered materials, limiting their potential in spintronic applications. Additionally, they do not meet the necessary symmetry requirements for nonrelativistic spin current. Here, we report the realization of C-paired SVL in a layered room-temperature antiferromagnetic compound, Rb1-{\delta}V2Te2O. Spin resolved photoemission measurements directly demonstrate the opposite spin splitting between C-paired valleys. Quasi-particle interference patterns reveal the suppression of inter-valley scattering due to the spin selection rules, as a direct consequence of C-paired SVL. All these experiments are well consistent with the results obtained from first-principles calculations. Our observations represent the first realization of layered antiferromagnets with C-paired SVL, enabling both the advantages of layered materials and possible control through crystal symmetry manipulation. These results hold significant promise and broad implications for advancements in magnetism, electronics, and information technology.