Band insulator to Mott insulator transition in 1T-TaS2

Wang, Y. D.; Yao, Weiliang; Zhang, Xin; Han, Tingting; Wang, Z. G.; Chen, L.; Cai, Changsi; Li, Yuan; Zhang, Yan

doi:10.1038/s41467-020-18040-4

Cited by 152 publications

(125 citation statements)

References 37 publications

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“… 14 , 26 Nonetheless, these options do not need to exclude each other necessarily since they can occur at different temperature regimes. 27 Thus, studying the out-of-plane correlations is a key element for understanding the underlying electronic and magnetic scenario occurring in 1T-TaS 2 .…”

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confidence: 99%

Out-of-Plane Transport of 1T-TaS₂/Graphene-Based van der Waals Heterostructures

et al. 2021

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Due to their anisotropy, layered materials are excellent candidates for studying the interplay between the in-plane and out-of-plane entanglement in strongly correlated systems. A relevant example is provided by 1T-TaS 2 , which exhibits a multifaceted electronic and magnetic scenario due to the existence of several charge density wave (CDW) configurations. It includes quantum hidden phases, superconductivity and exotic quantum spin liquid (QSL) states, which are highly dependent on the out-of-plane stacking of the CDW. In this system, the interlayer stacking of the CDW is crucial for interpreting the underlying electronic and magnetic phase diagram. Here, atomically thin-layers of 1T-TaS 2 are integrated in vertical van der Waals heterostructures based on few-layers graphene contacts and their electrical transport properties are measured. Different activation energies in the conductance and a gap at the Fermi level are clearly observed. Our experimental findings are supported by fully self-consistent DFT+U calculations, which evidence the presence of an energy gap in the few-layer limit, not necessarily coming from the formation of out-of-plane spin-paired bilayers at low temperatures, as previously proposed for the bulk. These results highlight dimensionality as a key effect for understanding quantum materials as 1T-TaS 2 , enabling the possible experimental realization of low-dimensional QSLs.

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confidence: 99%

Out-of-Plane Transport of 1T-TaS₂/Graphene-Based van der Waals Heterostructures

et al. 2021

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“…The complexity and diversity of the phase diagram and lattice structure of 1T-TaS2 displayed during the temperature change have aroused much research enthusiasm to this system, which stimulates public interest in studying the mechanism, exploring the potential possibilities of device application. In 2020, Zhang Wei, affiliated in PKU Quartz Material Center, plotted detailed temperaturemodified data of 1T-TaS2 (Figure 2), and discovered a new electron phase at around 217 K ~ 233K in the heating process [5]. As is shown in Figure 2, the 5d energy band of Ta atoms strips through the Fermi surface in the IC-CDW state.…”

Section: Literature Reviewmentioning

confidence: 97%

“…The temperature range in the research of Zhang et al, is 160 K ~ 300 K [5]. In this study, we set out to explore whether there is abnormal physical behavior at a temperature below 160 K?…”

Section: Literature Reviewmentioning

confidence: 99%

The Research on the Complexity of 1T-TaS2 at Ultra-low Temperatures

Han

2022

J. Phys.: Conf. Ser.

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Graphene, as a successfully industrialized two-dimensional material, has greatly promoted the development of other two-dimensional materials, such as transition metal dichalcogenide (TMDs). 1T-TaS2 is a classical TMDs material, which presents metallicity at high temperature. It undergoes a variety of charge density wave (CDW) phase transitions during the temperature declining process, and presents insulating properties at low temperature. During the temperature rise period, 1T-TaS2 goes through a phase transition, from an energy band insulator to Mott insulator, followed by an insulation-metal phase transition. The complexity of 1T-TaS2 phase diagram encourages researchers to conduct extensive research on it. This paper, via means of resistance, magnetic susceptibility and other technical methods, finds out that the ultra-low temperature of 1T-TaS2 suggests additional complexity. In addition, with the angle resolved photoemission spectroscopy (ARPES) technique of in-situ alkali metal evaporation, this paper proposes that the 1T-TaS2 ultra-low temperature ground state may exist a combination of state and surface state. Our findings provide more experimental evidence for the physical mechanism of this system.

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“…Considering that electrons can be conducted easily along the van der Waals bond i.e. in tantalum disulfide [48], hence the new weak chemical bonds with shorter bond lengths here can promote electrons to transport like a bridge, which will make the electron transfer easier.…”

Section: Partial (Band Decomposed) Charge Densities and Electron Loca...mentioning

confidence: 99%

Bridge role of weak chemical bonding in photocatalytic performance of asymmetric 2H-MoS₂/BiOCl Janus heterostructure

Zhao

Zhen-yi

et al. 2022

Mater. Res. Express

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The geometric and electronic structure, partial (band decomposed) charge density, charge transfer, electron localization function and photocatalytic mechanism of the asymmetric 2H-MoS2/BiOCl Janus heterostructure were systematically studied with first-principles density functional theory. Our calculations showed that there exist several newly formed weak Bi-S bonds with shorter bond lengths between BiOCl and 2H-MoS2 which act as an electron transport bridge along the direction perpendicular to the heterojunction interface. This newly weak bonds lead to the formation of occupied shallow defect levels approximately 0.0-0.9 eV below the bottom of the conduction band. Electrons located at these defect levels can easily jump into the conduction band as a donor energy level under thermal fluctuations and simultaneously further promote the effective separation of photo-generated electron-hole pairs in the BiOCl. The photogenerated electrons located around Bi-atom layer in the conduction band of BiOCl transfer to the valence band of 2H-MoS2 around the S-atom layer through the interface of the asymmetric 2H-MoS2/BiOCl Janus heterostructure, which significantly reduce photo-generated holes in the 2H-MoS2 and electrons in the BiOCl. The large numbers of photogenerated electrons from the 2H-MoS2 cannot recombine with holes owing to lack of sufficient holes. They will move to the surface and greatly improve the hydrogen production activity in the 2H-MoS2. While the photogenerated holes from the BiOCl will significantly improve the ability of BiOCl to oxidize pollutant in the water owing to the absence of sufficient electrons. Our studies provide new way for the design of asymmetric Janus double-layer heterostructures with newly formed weak chemical bonding.

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Band insulator to Mott insulator transition in 1T-TaS2

Cited by 152 publications

References 37 publications

Out-of-Plane Transport of 1T-TaS₂/Graphene-Based van der Waals Heterostructures

Out-of-Plane Transport of 1T-TaS₂/Graphene-Based van der Waals Heterostructures

The Research on the Complexity of 1T-TaS2 at Ultra-low Temperatures

Bridge role of weak chemical bonding in photocatalytic performance of asymmetric 2H-MoS₂/BiOCl Janus heterostructure

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Band insulator to Mott insulator transition in 1T-TaS2

Cited by 152 publications

References 37 publications

Out-of-Plane Transport of 1T-TaS2/Graphene-Based van der Waals Heterostructures

Out-of-Plane Transport of 1T-TaS2/Graphene-Based van der Waals Heterostructures

The Research on the Complexity of 1T-TaS2 at Ultra-low Temperatures

Bridge role of weak chemical bonding in photocatalytic performance of asymmetric 2H-MoS2/BiOCl Janus heterostructure

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Product

Resources

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Out-of-Plane Transport of 1T-TaS₂/Graphene-Based van der Waals Heterostructures

Out-of-Plane Transport of 1T-TaS₂/Graphene-Based van der Waals Heterostructures

Bridge role of weak chemical bonding in photocatalytic performance of asymmetric 2H-MoS₂/BiOCl Janus heterostructure