Spectroscopic signatures of a bandwidth-controlled Mott transition at the surface of 1T-TaSe$_2$

TL;DR

This study reveals a temperature-driven Mott transition at the surface of TaSe₂, characterized by spectral weight transfer observed via ARPES, supported by dynamical mean-field theory calculations of the Hubbard model.

Contribution

It demonstrates the bandwidth-controlled Mott transition at the surface of TaSe₂ and links it to atomic position modulations affecting the electronic structure.

Findings

ARPEs data shows a Mott transition at the surface of TaSe₂.

Spectral weight shifts from quasiparticle peak to Hubbard bands.

Theoretical calculations qualitatively match experimental observations.

Abstract

High-resolution angle-resolved photoemission (ARPES) data show that a metal-insulator Mott transition occurs at the surface of the quasi-two dimensional compound TaSe$_2$. The transition is driven by the narrowing of the Ta $5d$ band induced by a temperature-dependent modulation of the atomic positions. A dynamical mean-field theory calculation of the spectral function of the half-filled Hubbard model captures the main qualitative feature of the data, namely the rapid transfer of spectral weight from the observed quasiparticle peak at the Fermi surface to the Hubbard bands, as the correlation gap opens up.