Designing Flat Bands, Localized and Itinerant States in TaS2 Trilayer Heterostructures

Fuente: arXiv
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Autori principali: Bae, Hyeonhu, Valenti, Roser, Mazin, Igor I., Yan, Binghai
Natura: Preprint
Pubblicazione: 2025
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author Bae, Hyeonhu
Valenti, Roser
Mazin, Igor I.
Yan, Binghai
author_facet Bae, Hyeonhu
Valenti, Roser
Mazin, Igor I.
Yan, Binghai
contents Stacking and twisting van der Waals materials provide a powerful tool to design quantum matter and engineer electron correlation. For instance, monolayers of 1T- and 1H-TaS2 are Mott insulating and metallic (also superconducting), respectively, and thus, the T/H bilayer systems have been extensively investigated in the context of heavy fermions and unconventional superconductivity, which are expected phases from localized spins (1T) coexisting with itinerant electrons (1H). However, recent studies revealed that significant charge transfer from the 1T to 1H layers removes the 1T Mottness and renders the above scenario elusive. In this work, we propose a T/T/H trilayer heterostructure by combining a T/T bilayer -- which is a band insulator with flat dispersion -- with a 1H layer. After charge redistribution, this trilayer heterostructure shows localized spins in the Mott flat band of the T/T bilayer and weak spin polarization in the metallic H layer. We argue that by varying the stacking configurations of the T/T bilayer in the T/T/H trilayer, a crossover from a doped Mott insulator to a Kondo insulator can be achieved. The T/T/H trilayer provides therefore a rich novel heterostructure platform to study strong correlation phenomena and unconventional superconductivity.
format Preprint
id arxiv_https___arxiv_org_abs_2502_08793
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Designing Flat Bands, Localized and Itinerant States in TaS2 Trilayer Heterostructures
Bae, Hyeonhu
Valenti, Roser
Mazin, Igor I.
Yan, Binghai
Materials Science
Stacking and twisting van der Waals materials provide a powerful tool to design quantum matter and engineer electron correlation. For instance, monolayers of 1T- and 1H-TaS2 are Mott insulating and metallic (also superconducting), respectively, and thus, the T/H bilayer systems have been extensively investigated in the context of heavy fermions and unconventional superconductivity, which are expected phases from localized spins (1T) coexisting with itinerant electrons (1H). However, recent studies revealed that significant charge transfer from the 1T to 1H layers removes the 1T Mottness and renders the above scenario elusive. In this work, we propose a T/T/H trilayer heterostructure by combining a T/T bilayer -- which is a band insulator with flat dispersion -- with a 1H layer. After charge redistribution, this trilayer heterostructure shows localized spins in the Mott flat band of the T/T bilayer and weak spin polarization in the metallic H layer. We argue that by varying the stacking configurations of the T/T bilayer in the T/T/H trilayer, a crossover from a doped Mott insulator to a Kondo insulator can be achieved. The T/T/H trilayer provides therefore a rich novel heterostructure platform to study strong correlation phenomena and unconventional superconductivity.
title Designing Flat Bands, Localized and Itinerant States in TaS2 Trilayer Heterostructures
topic Materials Science
url https://arxiv.org/abs/2502.08793