Ab-initio study of the energy competition between Γand K valleys in bilayer transition metal dichalcogenides

Fuente: arXiv
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Autores principales: Olin, Sam, Jmukhadze, Erekle, MacDonald, Allan H., Lee, Wei-Cheng
Formato: Preprint
Publicado: 2023
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author Olin, Sam
Jmukhadze, Erekle
MacDonald, Allan H.
Lee, Wei-Cheng
author_facet Olin, Sam
Jmukhadze, Erekle
MacDonald, Allan H.
Lee, Wei-Cheng
contents Moiré engineering in two-dimensional van der Waals bilayer crystals has emerged as a flexible platform for controlling strongly correlated electron systems. The competition between valleys for the band extremum energy position in the parent layers is crucial in deciding the qualitative nature of the moiré Hamiltonian since it controls the physics of the moiré minibands. Here we use density functional theory to examine the competition between K and $Γ$ for the valence band maximum in homo- and hetero-bilayers formed from the transition metal dichalcogenides (TMD), MX\{_2} where M=Mo,W and X=S,Se,Te. We shed light on how the competition is influenced by interlayer separation, which can be modified by applying pressure, by external gate-defined electric fields, and by transition metal atom d-orbital correlations. Our findings are related to several recent experiments, and contribute to the development of design rules for moiré materials.
format Preprint
id arxiv_https___arxiv_org_abs_2310_17824
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Ab-initio study of the energy competition between Γand K valleys in bilayer transition metal dichalcogenides
Olin, Sam
Jmukhadze, Erekle
MacDonald, Allan H.
Lee, Wei-Cheng
Materials Science
Moiré engineering in two-dimensional van der Waals bilayer crystals has emerged as a flexible platform for controlling strongly correlated electron systems. The competition between valleys for the band extremum energy position in the parent layers is crucial in deciding the qualitative nature of the moiré Hamiltonian since it controls the physics of the moiré minibands. Here we use density functional theory to examine the competition between K and $Γ$ for the valence band maximum in homo- and hetero-bilayers formed from the transition metal dichalcogenides (TMD), MX\{_2} where M=Mo,W and X=S,Se,Te. We shed light on how the competition is influenced by interlayer separation, which can be modified by applying pressure, by external gate-defined electric fields, and by transition metal atom d-orbital correlations. Our findings are related to several recent experiments, and contribute to the development of design rules for moiré materials.
title Ab-initio study of the energy competition between Γand K valleys in bilayer transition metal dichalcogenides
topic Materials Science
url https://arxiv.org/abs/2310.17824