Exploring the Charge Density Wave Phase of 1T-TaSe2: Mott or Charge-Transfer Gap

C. J. Sayers; G. Cerullo; Y. Zhang; C. E. Sanders; R. T. Chapman; A. S. Wyatt; G. Chatterjee; E. Springate; D. Wolverson; E. Da Como; E. Carpene

doi:10.1103/PhysRevLett.130.156401

Exploring the Charge Density Wave Phase of 1T-TaSe2: Mott or Charge-Transfer Gap

C. J. Sayers, G. Cerullo, Y. Zhang, C. E. Sanders, R. T. Chapman, A. S. Wyatt, G. Chatterjee, E. Springate, D. Wolverson, E. Da Como, E. Carpene

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Abstract

1T-TaSe2 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-TaSe2. Our experimental results confirm the existence of a state above EF, previously ascribed to the upper Hubbard band, and an overall band gap of ∼0.7 eV at Γ¯. 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.

Original language	English
Article number	156401
Number of pages	6
Journal	Physical Review Letters
Volume	130
Issue number	15
DOIs	https://doi.org/10.1103/PhysRevLett.130.156401
Publication status	Published - 14 Apr 2023

Bibliographical note

Funding Information:
We acknowledge financial support from the Italian Ministry of University and Research (Grant No. PRIN 2017BZPKSZ) and LaserLab-Europe (Grant Agreement No. 871124, European Union’s Horizon 2020 research and innovation programme). Access to Artemis at the Central Laser Facility was provided by STFC (Experiment No. 20120002) with technical support from Alistair Cox, Phil Rice, and Ota Michalek. Computational work was also supported by the University of Bath Cloud Pilot Project and the EU Horizon 2020 OCRE project “Cloud funding for research.”

ASJC Scopus subject areas

General Physics and Astronomy

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10.1103/PhysRevLett.130.156401

https://arxiv.org/abs/2303.06188v1Licence: CC BY

Cite this

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title = "Exploring the Charge Density Wave Phase of 1T-TaSe2: Mott or Charge-Transfer Gap",

abstract = "1T-TaSe2 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-TaSe2. Our experimental results confirm the existence of a state above EF, previously ascribed to the upper Hubbard band, and an overall band gap of ∼0.7 eV at Γ¯. 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.",

author = "Sayers, {C. J.} and G. Cerullo and Y. Zhang and Sanders, {C. E.} and Chapman, {R. T.} and Wyatt, {A. S.} and G. Chatterjee and E. Springate and D. Wolverson and {Da Como}, E. and E. Carpene",

note = "Funding Information: We acknowledge financial support from the Italian Ministry of University and Research (Grant No. PRIN 2017BZPKSZ) and LaserLab-Europe (Grant Agreement No. 871124, European Union{\textquoteright}s Horizon 2020 research and innovation programme). Access to Artemis at the Central Laser Facility was provided by STFC (Experiment No. 20120002) with technical support from Alistair Cox, Phil Rice, and Ota Michalek. Computational work was also supported by the University of Bath Cloud Pilot Project and the EU Horizon 2020 OCRE project “Cloud funding for research.” ",

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T2 - Mott or Charge-Transfer Gap

AU - Sayers, C. J.

AU - Cerullo, G.

AU - Zhang, Y.

AU - Sanders, C. E.

AU - Chapman, R. T.

AU - Wyatt, A. S.

AU - Chatterjee, G.

AU - Springate, E.

AU - Wolverson, D.

AU - Da Como, E.

AU - Carpene, E.

N1 - Funding Information: We acknowledge financial support from the Italian Ministry of University and Research (Grant No. PRIN 2017BZPKSZ) and LaserLab-Europe (Grant Agreement No. 871124, European Union’s Horizon 2020 research and innovation programme). Access to Artemis at the Central Laser Facility was provided by STFC (Experiment No. 20120002) with technical support from Alistair Cox, Phil Rice, and Ota Michalek. Computational work was also supported by the University of Bath Cloud Pilot Project and the EU Horizon 2020 OCRE project “Cloud funding for research.”

PY - 2023/4/14

Y1 - 2023/4/14

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Exploring the Charge Density Wave Phase of 1T-TaSe2: Mott or Charge-Transfer Gap

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