Evolution of the Valley Position in Bulk Transition-Metal Chalcogenides and their Mono-Layer Limit
POSTER
Abstract
Layered transitionmetal chalcogenides have heavy elements with strong spin-orbit interaction, thus provide a unique way to extend functionalities of novel spintronics and valleytronics devices. Currently, most understanding of electronic bands near valleys is based on either theoretical calculations or optical measurements, leaving the detailed band structure elusive. In this talk, using angle-resolved photoemission spectroscopy with sub-micron spatial resolution, we systematically imaged the band structures and evolution across representative chalcogenides MoS$_{\mathrm{2}}$, WS$_{\mathrm{2}}$ and WSe$_{\mathrm{2}}$, as well as the thickness dependent from bulk to the monolayer limit. These results establish a solid basis to understand the underlying valley physics of these materials, and also provide a link between their electronic structures and physical properties for potential applications.