Evolution of the Fermi surface of 1T-VSe$_2$ across a structural phase transition

TL;DR

This study uses angle-resolved photoemission spectroscopy to investigate the electronic structure changes in 1T-VSe$_2$ during its structural phase transition, revealing new band components and clarifying their relation to the transition.

Contribution

It provides a detailed re-evaluation of the electronic origin of the phase transition, revealing previously missing band components and challenging the charge density wave explanation.

Findings

Band structure components are clarified and linked to the phase transition.

The size of the Fermi surface correlates with the transition at 110 K.

Previous temperature-independent features are explained by band complexity.

Abstract

The electronic origin of the structural transition in 1T-VSe$_2$ is re-evaluated through an extensive angle-resolved photoemission spectroscopy experiment. The components of the band structure, missing in previous reports, are revealed. Earlier observations, shown to be temperature independent and therefore not correlated with the phase transition, are explained in terms of the increased complexity of the band structure close to the Fermi level. Only the overall size of the Fermi surface is found to be positively correlated with the phase transition at 110 K. These observations, quite distant from the charge density wave scenario commonly considered for 1T-VSe$_2$, bring fresh perspectives toward the correct description of structural transitions in dichalcogenides materials.