Robust charge-density wave strengthened by electron correlations in monolayer 1T-TaSe2 and 1T-NbSe2

AbstractCombination of low-dimensionality and electron correlation is vital for exotic quantum phenomena such as the Mott-insulating phase and high-temperature superconductivity. Transition-metal dichalcogenide (TMD) 1T-TaS2 has evoked great interest owing to its unique nonmagnetic Mott-insulator nature coupled with a charge-density-wave (CDW). To functionalize such a complex phase, it is essential to enhance the CDW-Mott transition temperature TCDW-Mott, whereas this was difficult for bulk TMDs with TCDW-Mott < 200 K. Here we report a strong-coupling 2D CDW-Mott phase with a transition temperature onset of ~530 K in monolayer 1T-TaSe2. Furthermore, the electron correlation derived lower Hubbard band survives under external perturbations such as carrier doping and photoexcitation, in contrast to the bulk counterpart. The enhanced Mott-Hubbard and CDW gaps for monolayer TaSe2 compared to NbSe2, originating in the lattice distortion assisted by strengthened correlations and disappearance of interlayer hopping, suggest stabilization of a likely nonmagnetic CDW-Mott insulator phase well above the room temperature. The present result lays the foundation for realizing monolayer CDW-Mott insulator based devices operating at room temperature.

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Ultrafast manipulation of mirror domain walls in a charge density wave

Science Advances ◽

10.1126/sciadv.aau5501 ◽

2018 ◽

Vol 4 (10) ◽

pp. eaau5501 ◽

Cited By ~ 16

Author(s):

Alfred Zong ◽

Xiaozhe Shen ◽

Anshul Kogar ◽

Linda Ye ◽

Carolyn Marks ◽

...

Keyword(s):

Charge Density ◽

Charge Density Wave ◽

Room Temperature ◽

Domain Walls ◽

Density Wave ◽

Charge Ordering ◽

Time Resolved ◽

Insulator Metal Transition ◽

Femtosecond Light Pulse ◽

A Charge

Domain walls (DWs) are singularities in an ordered medium that often host exotic phenomena such as charge ordering, insulator-metal transition, or superconductivity. The ability to locally write and erase DWs is highly desirable, as it allows one to design material functionality by patterning DWs in specific configurations. We demonstrate such capability at room temperature in a charge density wave (CDW), a macroscopic condensate of electrons and phonons, in ultrathin 1T-TaS2. A single femtosecond light pulse is shown to locally inject or remove mirror DWs in the CDW condensate, with probabilities tunable by pulse energy and temperature. Using time-resolved electron diffraction, we are able to simultaneously track anti-synchronized CDW amplitude oscillations from both the lattice and the condensate, where photoinjected DWs lead to a red-shifted frequency. Our demonstration of reversible DW manipulation may pave new ways for engineering correlated material systems with light.

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Achieving Room‐Temperature Charge Density Wave in Transition Metal Dichalcogenide 1 T ‐VSe 2

Advanced Electronic Materials ◽

10.1002/aelm.201901427 ◽

2020 ◽

Vol 6 (5) ◽

pp. 1901427

Author(s):

Jiajia Feng ◽

Resta A. Susilo ◽

Bencheng Lin ◽

Wen Deng ◽

Yanju Wang ◽

...

Keyword(s):

Transition Metal ◽

Charge Density ◽

Charge Density Wave ◽

Room Temperature ◽

Density Wave ◽

Transition Metal Dichalcogenide

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A charge-density-wave oscillator based on an integrated tantalum disulfide–boron nitride–graphene device operating at room temperature

Nature Nanotechnology ◽

10.1038/nnano.2016.108 ◽

2016 ◽

Vol 11 (10) ◽

pp. 845-850 ◽

Cited By ~ 86

Author(s):

Guanxiong Liu ◽

Bishwajit Debnath ◽

Timothy R. Pope ◽

Tina T. Salguero ◽

Roger K. Lake ◽

...

Keyword(s):

Boron Nitride ◽

Charge Density ◽

Charge Density Wave ◽

Room Temperature ◽

Density Wave ◽

Wave Oscillator ◽

A Charge

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The Effects of Transition Metal Substitutions in the NbTe4-TaTe4 Charge-Density Wave System

Australian Journal of Chemistry ◽

10.1071/ch9921363 ◽

1992 ◽

Vol 45 (9) ◽

pp. 1363 ◽

Cited By ~ 3

Author(s):

JC Bennett ◽

FW Boswell ◽

A Prodan ◽

JM Corbett ◽

S Ritchie

Keyword(s):

Transition Metal ◽

Charge Density ◽

Charge Density Wave ◽

Room Temperature ◽

Density Wave ◽

Dark Field ◽

Wave System ◽

Incommensurate Modulation ◽

High Concentrations ◽

A Charge

At room temperature, the structures of TaTe4 and NbTe4 are modulated by the presence of a charge-density wave which in the former compound is commensurate with the parent lattice and in the latter incommensurate. In addition, a series of incommensurate mixed crystals ( Tal-xNbx )Te4 (0 ≤ x ≤) exist in which the modulation wavevector increases as a function of x. In this paper, we report the occurrence of a systematic variation in the period of the charge-density wave upon substitution of the transition metal elements Ti, Zr or V for either Nb or Ta. Electron diffraction experiments reveal that, in TaTe4, substitutions of Group 4 elements Ti and Zr result in an incommensurate modulation with a decrease in the modulation wavevector q. In NbTe4, substitutions of Ti or Zr also reduce q, in this case towards the commensurate value, and, at sufficiently high concentrations, a commensurate phase is stabilized at room temperature. Vanadium substitutions in NbTe4 result in a slight increase in q. Satellite dark-field images reveal the presence of defects in the modulation structures of the doped crystals. The above results are discussed in terms of the factors which determine the charge-density wave periodicity in the NbTe4-TaTe4 system.

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