Nanoscale Modulation of Flat Bands via Controllable Charge-Density-Waves Defects in 4Hb-TaS2

Fuente: arXiv
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Main Authors: Yang, Wooin, Karbasizadeh, Siavash, Jeon, Hoyeon, Hus, Saban, Baddorf, Arthur P., Mu, Sai, Berlijn, Tom, Zhou, Haidong, Ko, Wonhee, Li, An-Ping
Format: Preprint
Published: 2025
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author Yang, Wooin
Karbasizadeh, Siavash
Jeon, Hoyeon
Hus, Saban
Baddorf, Arthur P.
Mu, Sai
Berlijn, Tom
Zhou, Haidong
Ko, Wonhee
Li, An-Ping
author_facet Yang, Wooin
Karbasizadeh, Siavash
Jeon, Hoyeon
Hus, Saban
Baddorf, Arthur P.
Mu, Sai
Berlijn, Tom
Zhou, Haidong
Ko, Wonhee
Li, An-Ping
contents Electron correlation is a main driver of exotic quantum phases and their interplay. The 4Hb-TaS2 system, possessing intrinsic heterostructure of 1T- and 1H-TaS2 monolayers, offers a unique opportunity to control electron correlation by distorting the atomic lattice or tuning interlayer coupling. Here, we investigated intrinsically deformed charge-density-waves (CDW) in the 1T layer of 4Hb-TaS2 to elucidate and control their effects on flat bands using scanning tunneling microscopy and spectroscopy (STM/S) combined with first-principles calculations. We identified two types of CDW defects: Type 1 has structural distortion and locally suppressed flat bands, while Type 2 features an increased flat band filling factor of intact CDW structure. Density functional theory calculations indicate that a sulfur vacancy in the 1T layer distorts the CDW structure and gives rise to a Type 1, whereas a sulfur vacancy in the 1H layer reduces the interlayer charge transfer and lead to a Type 2. Furthermore, we demonstrated creating and erasing individual CDW defects via STM manipulation. Our findings provide a pathway to not only tune flat bands but also selectively manipulate the interaction between CDW, the atomic lattice, and interlayer coupling in strongly correlated systems with atomic precision.
format Preprint
id arxiv_https___arxiv_org_abs_2507_22736
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Nanoscale Modulation of Flat Bands via Controllable Charge-Density-Waves Defects in 4Hb-TaS2
Yang, Wooin
Karbasizadeh, Siavash
Jeon, Hoyeon
Hus, Saban
Baddorf, Arthur P.
Mu, Sai
Berlijn, Tom
Zhou, Haidong
Ko, Wonhee
Li, An-Ping
Strongly Correlated Electrons
Electron correlation is a main driver of exotic quantum phases and their interplay. The 4Hb-TaS2 system, possessing intrinsic heterostructure of 1T- and 1H-TaS2 monolayers, offers a unique opportunity to control electron correlation by distorting the atomic lattice or tuning interlayer coupling. Here, we investigated intrinsically deformed charge-density-waves (CDW) in the 1T layer of 4Hb-TaS2 to elucidate and control their effects on flat bands using scanning tunneling microscopy and spectroscopy (STM/S) combined with first-principles calculations. We identified two types of CDW defects: Type 1 has structural distortion and locally suppressed flat bands, while Type 2 features an increased flat band filling factor of intact CDW structure. Density functional theory calculations indicate that a sulfur vacancy in the 1T layer distorts the CDW structure and gives rise to a Type 1, whereas a sulfur vacancy in the 1H layer reduces the interlayer charge transfer and lead to a Type 2. Furthermore, we demonstrated creating and erasing individual CDW defects via STM manipulation. Our findings provide a pathway to not only tune flat bands but also selectively manipulate the interaction between CDW, the atomic lattice, and interlayer coupling in strongly correlated systems with atomic precision.
title Nanoscale Modulation of Flat Bands via Controllable Charge-Density-Waves Defects in 4Hb-TaS2
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2507.22736