Tungsten Ditelluride: A layered semimetal

Abstract

Tungsten ditelluride (WTe 2) is a transition metal dichalcogenide (TMD) with physical and electronic properties that make it attractive for a variety of electronic applications. Although WTe 2 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 WTe 2, and verify that WTe 2 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 WTe 2, introduce new information about the Raman modes of Td-WTe 2, and demonstrate that Td-WTe 2 is readily oxidized via environmental exposure. Finally, these findings confirm that, in its thermodynamically favored Td form, the utilization of WTe 2 in electronic device architectures such as field effect transistors may need to be reevaluated.