Epitaxial growth of quasi-one-dimensional TaNi₂Se₂ monolayer with anisotropic electronic and mechanical properties

Quasi-one-dimensional (quasi-1D) van der Waals layered materials have garnered significant interest for their intrinsic in-plane anisotropy and potential applications in low-dimensional quantum devices. Here, we report the realization of a quasi-1D TaNi₂Se₂ monolayer with pronounced anisotropic electronic and mechanical properties. The monolayer TaNi₂Se₂ is synthesized on a graphite substrate via van der Waals epitaxy. Using low-temperature scanning tunneling microscopy/spectroscopy, we reveal the characteristic quasi-1D chain-like lattice structure and confirm the intrinsic metallic nature of the monolayer TaNi₂Se₂. Notably, the electronic states exhibit a pronounced quasi-1D modulation that follows the chain structure, indicating strong electronic anisotropy. First-principles calculations further confirm the structural stability and provide signatures of anisotropic in-plane mechanical properties, as well as possible topological edge states arising from spin–orbit coupling. Our findings establish monolayer TaNi₂Se₂ as a novel quasi-1D van der Waals material and provide a promising platform for exploring anisotropy-driven quantum phenomena and device applications.