Layer photovoltaic effect in a two-dimensional antiferromagnet with parity-time symmetry.

Antiferromagnets with parity-time symmetry host intriguing optical and transport phenomena governed by quantum metric, as the counterpart, Berry curvature, vanishes under parity-time symmetry. In antiferromagnets with parity-time symmetry, the intrinsic photovoltaic effect, driven by the interband quantum metric associated with optically allowed transitions, is expected due to the inversion symmetry breaking induced by antiferromagnetic order, but experimental demonstration has remained elusive. Here we report the experimental observation of an intrinsic photovoltaic effect in a two-dimensional antiferromagnet with parity-time symmetry, bilayer CrSBr. Notably, the intrinsic photocurrent reverses sign according to the antiferromagnetic configurations. Moreover, by manipulating the magnetic field and device architecture (the top and bottom contacts), we distinctly identify layer-resolved intrinsic photocurrent responses. A tight-binding model based on the band-resolved quantum-metric-driven magnetic injection current mechanism is proposed to interpret these observations and reveal the layer-localized nature of the quantum metric. Our findings provide a promising strategy for developing switchable photovoltaic devices and engineering the spatial quantum geometry in layered antiferromagnets.