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arXiv · 1910.14607

Realization of metallic state in 1T-TaS2 with persisting long-range order of charge density wave

Xin-Yang Zhu·Shi Wang·Zhen-Yu Jia·Li Zhu·Qi-Yuan Li·Wei-Min Zhao·Cheng-Long Xue·Yong-Jie Xu·Zhen Ma·Jinsheng Wen·Shun-Li Yu·Jian-Xin Li·Shao-Chun Li
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Abstract

Metallization of 1T-TaS2 is generally initiated at the domain boundary of charge density wave (CDW), at the expense of its long-range order. However, we demonstrate in this study that the metallization of 1T-TaS2 can be also realized without breaking the long-range CDW order upon surface alkali doping. By using scanning tunneling microscopy, we find the long-range CDW order is always persisting, and the metallization is instead associated with additional in-gap excitations. Interestingly, the in-gap excitation is near the top of the lower Hubbard band, in contrast to a conventional electron-doped Mott insulator where it is beneath the upper Hubbard band. In combination with the numerical calculations, we suggest that the appearance of the in-gap excitations near the lower Hubbard band is mainly due to the effectively reduced on-site Coulomb energy by the adsorbed alkali ions.

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Xin-Yang Zhu, Shi Wang, Zhen-Yu Jia, Li Zhu, Qi-Yuan Li, Wei-Min Zhao, Cheng-Long Xue, Yong-Jie Xu, Zhen Ma, Jinsheng Wen, Shun-Li Yu, Jian-Xin Li, Shao-Chun Li. 2019-10-31. Realization of metallic state in 1T-TaS2 with persisting long-range order of charge density wave. https://doi.org/10.1103/physrevlett.123.206405

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