%0 Journal Article
%T Anisotropic band splitting in monolayer NbSe2: implications for superconductivity and charge density wave
%J -
%D 2018
%R https://doi.org/10.1038/s41699-018-0057-3
%X Realization of unconventional physical properties in two-dimensional (2D) transition-metal dichalcogenides (TMDs) is currently one of the key challenges in condensed-matter systems. However, the electronic properties of 2D TMDs remain largely unexplored compared to those of their bulk counterparts. Here, we report the fabrication of a high-quality monolayer NbSe2 film with a trigonal prismatic structure by molecular beam epitaxy, and the study of its electronic properties by scanning tunneling microscopy, angle-resolved photoemission spectroscopy, and electrical transport measurements, together with first-principles band-structure calculations. In addition to a charge density wave (CDW) with 3£¿¡Á£¿3 periodicity and superconductivity below 1.5£¿K, we observed sizable (~0.1£¿eV) band splitting along the ¦£-K cut in the Brillouin zone due to inversion symmetry breaking in the monolayer crystal. This splitting is highly anisotropic in k space, leading to a spin-split van-Hove singularity in the band structure. The present results suggest the importance of spin¨Corbit coupling and symmetry breaking for unconventional superconductivity and CDW properties in monolayer TMDs
%U https://www.nature.com/articles/s41699-018-0057-3