Designing flat bands, localized and itinerant states in TaS2 trilayer heterostructures

Abstract Stacking and twisting van der Waals materials provides a powerful tool to engineer quantum matter. For instance, 1T-TaS2 monolayers are Mott insulators, whereas layered 1H-TaS2 is metallic and superconducting; thus, the T/H bilayer, where heavy fermions and unconventional superconducting ph...

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Main Authors: Hyeonhu Bae, Roser Valentí, Igor I. Mazin, Binghai Yan
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:npj Quantum Materials
Online Access:https://doi.org/10.1038/s41535-025-00812-0
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author Hyeonhu Bae
Roser Valentí
Igor I. Mazin
Binghai Yan
author_facet Hyeonhu Bae
Roser Valentí
Igor I. Mazin
Binghai Yan
author_sort Hyeonhu Bae
collection DOAJ
description Abstract Stacking and twisting van der Waals materials provides a powerful tool to engineer quantum matter. For instance, 1T-TaS2 monolayers are Mott insulators, whereas layered 1H-TaS2 is metallic and superconducting; thus, the T/H bilayer, where heavy fermions and unconventional superconducting phases are expected from localized spins (1T) coexisting with itinerant electrons (1H), has been intensively studied. However, recent studies revealed significant charge transfer that questions this scenario. Here, we propose a T/T/H trilayer heterostructure where the T/T bilayer is a flat-dispersion band insulator with localized electrons, whereas the 1H layer remains metallic with a weak spin polarization. Varying the T/T stacking configuration tunes the flat-band filling, enabling a crossover from a doped-Mott regime to a Kondo-like state. Such a trilayer heterostructure provides, therefore, a rich novel platform to study strong correlation phenomena and unconventional superconductivity.
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institution Kabale University
issn 2397-4648
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publisher Nature Portfolio
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series npj Quantum Materials
spelling doaj-art-438dc821452c4d24b63eeb115b58a18e2025-08-24T11:06:21ZengNature Portfolionpj Quantum Materials2397-46482025-08-011011610.1038/s41535-025-00812-0Designing flat bands, localized and itinerant states in TaS2 trilayer heterostructuresHyeonhu Bae0Roser Valentí1Igor I. Mazin2Binghai Yan3Department of Condensed Matter Physics, Weizmann Institute of ScienceInstitute für Theoretische Physik, Goethe-Universität FrankfurtDepartment of Physics and Astronomy, George Mason UniversityDepartment of Condensed Matter Physics, Weizmann Institute of ScienceAbstract Stacking and twisting van der Waals materials provides a powerful tool to engineer quantum matter. For instance, 1T-TaS2 monolayers are Mott insulators, whereas layered 1H-TaS2 is metallic and superconducting; thus, the T/H bilayer, where heavy fermions and unconventional superconducting phases are expected from localized spins (1T) coexisting with itinerant electrons (1H), has been intensively studied. However, recent studies revealed significant charge transfer that questions this scenario. Here, we propose a T/T/H trilayer heterostructure where the T/T bilayer is a flat-dispersion band insulator with localized electrons, whereas the 1H layer remains metallic with a weak spin polarization. Varying the T/T stacking configuration tunes the flat-band filling, enabling a crossover from a doped-Mott regime to a Kondo-like state. Such a trilayer heterostructure provides, therefore, a rich novel platform to study strong correlation phenomena and unconventional superconductivity.https://doi.org/10.1038/s41535-025-00812-0
spellingShingle Hyeonhu Bae
Roser Valentí
Igor I. Mazin
Binghai Yan
Designing flat bands, localized and itinerant states in TaS2 trilayer heterostructures
npj Quantum Materials
title Designing flat bands, localized and itinerant states in TaS2 trilayer heterostructures
title_full Designing flat bands, localized and itinerant states in TaS2 trilayer heterostructures
title_fullStr Designing flat bands, localized and itinerant states in TaS2 trilayer heterostructures
title_full_unstemmed Designing flat bands, localized and itinerant states in TaS2 trilayer heterostructures
title_short Designing flat bands, localized and itinerant states in TaS2 trilayer heterostructures
title_sort designing flat bands localized and itinerant states in tas2 trilayer heterostructures
url https://doi.org/10.1038/s41535-025-00812-0
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AT igorimazin designingflatbandslocalizedanditinerantstatesintas2trilayerheterostructures
AT binghaiyan designingflatbandslocalizedanditinerantstatesintas2trilayerheterostructures