Electronic states of multilayer VTe2: quasi-one-dimensional Fermi surface and implications to charge-density waves

TL;DR

This study uses angle-resolved photoemission spectroscopy to explore how the electronic structure and Fermi surface shape in VTe2 films influence charge-density wave behavior, revealing a transition from 2D to quasi-1D Fermi surfaces with thickness.

Contribution

It demonstrates the evolution of Fermi surface topology in VTe2 films and links structural phase changes to charge-density wave properties, providing insights for manipulating CDWs in ultrathin TMDs.

Findings

Transition from 2D triangular to quasi-1D Fermi surface with increasing thickness

Distinct electronic behaviors in 1ML and 6ML VTe2 related to CDW

First-principles calculations support experimental Fermi surface observations

Abstract

We have performed angle-resolved photoemission spectroscopy on epitaxial VTe2 films to elucidate the relationship between the fermiology and charge-density waves (CDW). We found that a two-dimensional triangular pocket in 1 monolayer (ML) VTe2 is converted to a strongly warped quasi-one-dimensional (1D) Fermi surface in the 6ML counterpart, likely associated with the 1T-to-1T' structural phase transition. We also revealed a metallic Fermi edge on the entire Fermi surface in 6ML at low temperature distinct from anisotropic pseudogap in 1ML, signifying a contrast behavior of CDW that is also supported by first-principles band-structure caluculations. The present result points to the importance of simultaneously controlling the structural phase and fermiology to manipulate the CDW properties in ultrathin transition-metal dichalcogenides.