High-Efficiency Nonrelativistic Charge-Spin Conversion in X-Type Antiferromagnets

TL;DR

This paper demonstrates highly efficient nonrelativistic charge-spin conversion in X-type antiferromagnets, leveraging their unique Fermi surface geometry to achieve up to 90% efficiency and control spin current polarization via Néel vector orientation.

Contribution

It reveals that the distinctive Fermi surface of X-type antiferromagnets enables unprecedented charge-spin conversion efficiency and spin current control, advancing spintronic device potential.

Findings

Charge-spin conversion efficiency up to 90%

Spin current polarization controlled by Ne9el vector orientation

Out-of-plane spin current component with enhanced efficiency

Abstract

Antiferromagnetic materials with spin splitting have attracted considerable attention for their symmetry-enabled anisotropic spin textures that sustain a zero net magnetization, thereby facilitating efficient spin-current generation. In this work, the highly efficient generation of nonrelativistic spin currents is demonstrated to be facilitated by the distinctive Fermi surface geometry of X-type collinear antiferromagnets. As a prototype conducting X-type antiferromagnet, the Fermi surface of $\beta-\mathrm{Fe_2PO_5}$ exhibits a distinct $d$-wave altermagnetic characteristic, which compresses into a nearly X-shaped configuration. This results in highly efficient spin currents, achieving a charge-spin conversion efficiency of up to 90\%. Moreover, the spin current polarization is controlled by the orientation of the N\'eel vector. When the N\'eel vector tilts to the out-of-plane direction, an in-plane injected charge current can generate a special spin current component with both spin polarization and propagation along the out-of-plane direction, whose charge-spin conversion efficiency substantially exceeds that of known ferromagnets, altermagnets, noncollinear antiferromagnets, and low-symmetry materials. The highly efficient charge-spin conversion in X-type antiferromagnets provides a novel and highly effective spin source system for the development of low-power spintronic devices.