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Main Authors: Chen, Haiyang, Wang, Fo-Hong, Gao, Qiang, Gao, Xue-Jian, Chen, Zhenhua, Huang, Yaobo, Law, Kam Tuen, Xu, Xiao Yan, Chen, Peng
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2504.11778
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author Chen, Haiyang
Wang, Fo-Hong
Gao, Qiang
Gao, Xue-Jian
Chen, Zhenhua
Huang, Yaobo
Law, Kam Tuen
Xu, Xiao Yan
Chen, Peng
author_facet Chen, Haiyang
Wang, Fo-Hong
Gao, Qiang
Gao, Xue-Jian
Chen, Zhenhua
Huang, Yaobo
Law, Kam Tuen
Xu, Xiao Yan
Chen, Peng
contents Mott insulators with localized magnetic moments will exhibit a quantum spin liquid (QSL) state when the quantum fluctuations are strong enough to suppress the ordering of the spins. Such an entangled state will give rise to collective excitations, in which spin and charge information are carried separately. Our angle-resolved photoemission spectroscopy (ARPES) measurements on single-layer 1T-TaS2 show a flat band around the zone center and a gap opening of about 200 meV in the low temperature, indicating 2D Mott insulating nature in the system. This flat band is dispersionless in momentum space but shows anomalously broad width around the zone center and the spectral weight decays rapidly as momentum increases. The observation is described as a spectral continuum from electron fractionalization, corroborated by a low energy effective model.The intensity of the flat band is reduced by surface doping with magnetic adatoms and the gap is closing, a result from the interaction between spin impurities coupled with spinons and the chargons, which gives rise to a charge redistribution. Doping with nonmagnetic impurities behaves differently as the chemical potential shift dominates. These findings provide insight into the QSL states of strongly correlated electrons on 2D triangular lattices.
format Preprint
id arxiv_https___arxiv_org_abs_2504_11778
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spectroscopic evidence for possible quantum spin liquid behavior in a two-dimensional Mott insulator
Chen, Haiyang
Wang, Fo-Hong
Gao, Qiang
Gao, Xue-Jian
Chen, Zhenhua
Huang, Yaobo
Law, Kam Tuen
Xu, Xiao Yan
Chen, Peng
Strongly Correlated Electrons
Mott insulators with localized magnetic moments will exhibit a quantum spin liquid (QSL) state when the quantum fluctuations are strong enough to suppress the ordering of the spins. Such an entangled state will give rise to collective excitations, in which spin and charge information are carried separately. Our angle-resolved photoemission spectroscopy (ARPES) measurements on single-layer 1T-TaS2 show a flat band around the zone center and a gap opening of about 200 meV in the low temperature, indicating 2D Mott insulating nature in the system. This flat band is dispersionless in momentum space but shows anomalously broad width around the zone center and the spectral weight decays rapidly as momentum increases. The observation is described as a spectral continuum from electron fractionalization, corroborated by a low energy effective model.The intensity of the flat band is reduced by surface doping with magnetic adatoms and the gap is closing, a result from the interaction between spin impurities coupled with spinons and the chargons, which gives rise to a charge redistribution. Doping with nonmagnetic impurities behaves differently as the chemical potential shift dominates. These findings provide insight into the QSL states of strongly correlated electrons on 2D triangular lattices.
title Spectroscopic evidence for possible quantum spin liquid behavior in a two-dimensional Mott insulator
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2504.11778