Exploring the Charge Density Wave Phase of 1T-TaSe_{2}: Mott or Charge-Transfer Gap?


Journal

Physical review letters
ISSN: 1079-7114
Titre abrégé: Phys Rev Lett
Pays: United States
ID NLM: 0401141

Informations de publication

Date de publication:
14 Apr 2023
Historique:
received: 10 10 2022
revised: 29 12 2022
accepted: 02 03 2023
medline: 28 4 2023
pubmed: 28 4 2023
entrez: 28 4 2023
Statut: ppublish

Résumé

1T-TaSe_{2} is widely believed to host a Mott metal-insulator transition in the charge density wave (CDW) phase according to the spectroscopic observation of a band gap that extends across all momentum space. Previous investigations inferred that the occurrence of the Mott phase is limited to the surface only of bulk specimens, but recent analysis on thin samples revealed that the Mott-like behavior, observed in the monolayer, is rapidly suppressed with increasing thickness. Here, we report combined time- and angle-resolved photoemission spectroscopy and theoretical investigations of the electronic structure of 1T-TaSe_{2}. Our experimental results confirm the existence of a state above E_{F}, previously ascribed to the upper Hubbard band, and an overall band gap of ∼0.7  eV at Γ[over ¯]. However, supported by density functional theory calculations, we demonstrate that the origin of this state and the gap rests on band structure modifications induced by the CDW phase alone, without the need for Mott correlation effects.

Identifiants

pubmed: 37115877
doi: 10.1103/PhysRevLett.130.156401
doi:

Types de publication

Journal Article

Langues

eng

Sous-ensembles de citation

IM

Pagination

156401

Auteurs

C J Sayers (CJ)

Dipartimento di Fisica, Politecnico di Milano, Milan 20133, Italy.

G Cerullo (G)

Dipartimento di Fisica, Politecnico di Milano, Milan 20133, Italy.

Y Zhang (Y)

STFC Central Laser Facility, Research Complex at Harwell, Harwell Campus, Didcot OX11 0QX, United Kingdom.

C E Sanders (CE)

STFC Central Laser Facility, Research Complex at Harwell, Harwell Campus, Didcot OX11 0QX, United Kingdom.

R T Chapman (RT)

STFC Central Laser Facility, Research Complex at Harwell, Harwell Campus, Didcot OX11 0QX, United Kingdom.

A S Wyatt (AS)

STFC Central Laser Facility, Research Complex at Harwell, Harwell Campus, Didcot OX11 0QX, United Kingdom.

G Chatterjee (G)

STFC Central Laser Facility, Research Complex at Harwell, Harwell Campus, Didcot OX11 0QX, United Kingdom.

E Springate (E)

STFC Central Laser Facility, Research Complex at Harwell, Harwell Campus, Didcot OX11 0QX, United Kingdom.

D Wolverson (D)

Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.

E Da Como (E)

Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.

E Carpene (E)

IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Milan 20133, Italy.

Classifications MeSH