Microscopic Imaging of Magnetic Domains through Anomalous Photo-Nernst Effect in Co3Sn2S2 Nanoplates.

Magnetic domain imaging technologies are critical to both fundamental physics and various application fields, such as magnetic storage and spintronics. The observation of magnetic domains using light, typically based on magneto-optical microscopy, is one of the most effective techniques for visualizing magnetic domains with micrometer resolution. In this work, we demonstrate an alternative approach based on the anomalous photo-Nernst effect that is applicable to magnetic Weyl semimetals. Through scanning photocurrent microscopy, we observe a pronounced photocurrent at the domain wall, arising from the local thermal diffusion of carriers under different magnetization directions via the anomalous Nernst effect, enabling the microscopic imaging of magnetic domains. Comparing with methods based on the magneto-optical Kerr effect and magnetic circular dichroism, which rely on the different response to the left and right circularly polarized light and typically require additional fast polarization modulation, the reported approach offers a convenient and reliable method without any intentional light polarization control.