Crystal Symmetry Selected Pure Spin Photocurrent in Altermagnetic Insulators

Abstract

The generation of time-reversal-odd spin-current in metallic altermagnets has attracted considerable interest in spintronics. However, producing pure spin-current in insulating materials remains both challenging and desirable, as insulating states are frequently found in antiferromagnets. Nonlinear photogalvanic effects offer a promising method for generating spin-current in insulators. We here revealed that spin and charge photocurrents in altermagnets are protected by spin point group symmetry. Unlike the photocurrents in parity-time symmetric materials, where spin-orbit coupling (SOC) induces a significant charge current, the spin-current in altermagnets can exist as a pure spin current along specific crystal directions regardless of SOC. We applied our predictions using first-principles calculations to several distinct materials, including wurtzite MnTe and multiferroic BiFeO3. Additionally, we elucidated the previously overlooked linear-inject-current mechanism in BiFeO3 induced by SOC, which may account for the enhanced bulk photovotaic effect in multiferroics.

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Cited by in corpus (5)

• G-type Antiferromagnetic BiFeO${}_3$ is a Multiferroic $g$-wave Altermagnet
• Dynamical Generation of Higher-order Spin-Orbit Couplings, Topology and Persistent Spin Texture in Light-Irradiated Altermagnets
• Lithium and Vanadium Intercalation into Bilayer V2Se2O: Ferrimagnetic-Ferroelastic Multiferroics and Anomalous and Spin Transport
• Dimension- and Facet-Dependent Altermagnetic Biferroics and Ferromagnetic Biferroics and Triferroics in CrSb
• Symmetry-driven Intrinsic Nonlinear Pure Spin Hall Effect