Weyl-Related Surface Circular Photogalvanic Effect in Nonsymmorphic-Symmetry ZrGeTe4 Semiconductor

Weyl semiconductors, combining the high tunability features of semiconductors with the exotic topological properties of Weyl materials, are of great significance for fundamental physics studies and functional topological devices. Despite the potential theoretical implications, few Weyl semiconductors are experimentally discovered. Chirality is an extraordinary feature of Weyl nodes, which can give rise to helicity-resolved photocurrents, known as the circular photogalvanic effect (CPGE). Here, this work discloses the surface CPGE in nonsymmorphic-symmetry ZrGeTe 4 semiconductors via a specific excitation and detection geometry, demonstrating that it originates from asymmetric helicity-dependent optical transitions between two Kramers–Weyl nodes in the conduction and valence bands. Wavelength-dependent experiments support the chirality-related Weyl features of the CPGE in ZrGeTe 4 semiconductors. It is experimentally confirmed that the Weyl-related surface CPGE is an intrinsic phenomenon that can be flexibly tuned with an in-plane electric field. The work provides a new platform for designing spintronic, optoelectronic, and quantum devices by integrating the advantages of topological materials with versatile semiconductors.