Tungsten Ditelluride: A layered semimetal

Tungsten ditelluride (WTe₂) is a transition metal dichalcogenide (TMD) with physical and electronic properties that make it attractive for a variety of electronic applications. Although WTe₂ has been studied for decades, its structure and electronic properties have only recently been correctly described. We experimentally and theoretically investigate the structure, dynamics and electronic properties of WTe₂, and verify that WTe₂ has its minimum energy configuration in a distorted 1T structure (Td structure), which results in metallic-like transport. Our findings unambiguously confirm the metallic nature of WTe₂, introduce new information about the Raman modes of Td-WTe₂, and demonstrate that Td-WTe₂ is readily oxidized via environmental exposure. Finally, these findings confirm that, in its thermodynamically favored Td form, the utilization of WTe₂ in electronic device architectures such as field effect transistors may need to be reevaluated.