Dynamical control of Coulomb interactions and Hubbard bands in monolayer 1T-TaS$_2$

Fuente: arXiv
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Main Authors: Notter, Niklas, Aichhorn, Markus, Galler, Anna
Format: Preprint
Published: 2025
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author Notter, Niklas
Aichhorn, Markus
Galler, Anna
author_facet Notter, Niklas
Aichhorn, Markus
Galler, Anna
contents Monolayer 1T-TaS$_2$ hosts a star-of-David charge-density wave (CDW) that stabilizes a low-temperature Mott-insulating state. Recent time-resolved spectroscopies indicate a coupling between the CDW amplitude mode and the electronic correlation strength, yet the role of the screened Coulomb interaction remains unclear. Using the constrained random-phase approximation, we show that the CDW amplitude modifies the bare and screened on-site interactions, leading to sizable variations in the effective Hubbard U. Our combined density functional and dynamical mean-field theory calculations reveal that the Hubbard bands shift in concert with the CDW amplitude, and that a reduced distortion drives a transition from a Mott insulator to a correlated metal. These results demonstrate a direct link between lattice distortions and Coulomb interactions in transition-metal dichalcogenides, providing a microscopic mechanism for light-induced control of correlated phases in two-dimensional quantum materials.
format Preprint
id arxiv_https___arxiv_org_abs_2510_26584
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dynamical control of Coulomb interactions and Hubbard bands in monolayer 1T-TaS$_2$
Notter, Niklas
Aichhorn, Markus
Galler, Anna
Strongly Correlated Electrons
Materials Science
Monolayer 1T-TaS$_2$ hosts a star-of-David charge-density wave (CDW) that stabilizes a low-temperature Mott-insulating state. Recent time-resolved spectroscopies indicate a coupling between the CDW amplitude mode and the electronic correlation strength, yet the role of the screened Coulomb interaction remains unclear. Using the constrained random-phase approximation, we show that the CDW amplitude modifies the bare and screened on-site interactions, leading to sizable variations in the effective Hubbard U. Our combined density functional and dynamical mean-field theory calculations reveal that the Hubbard bands shift in concert with the CDW amplitude, and that a reduced distortion drives a transition from a Mott insulator to a correlated metal. These results demonstrate a direct link between lattice distortions and Coulomb interactions in transition-metal dichalcogenides, providing a microscopic mechanism for light-induced control of correlated phases in two-dimensional quantum materials.
title Dynamical control of Coulomb interactions and Hubbard bands in monolayer 1T-TaS$_2$
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2510.26584