Realization of a Metallic State in 1T-TaS2 with Persisting Long-Range Order of a Charge Density Wave
Realization of a Metallic State in 1T-TaS2 with Persisting Long-Range Order of a Charge Density Wave
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具有持久电荷密度波长程有序的 1T-TaS2 金属态的实现
DOI：
10.1103/physrevlett.123.206405
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发表时间：
2019
影响因子：
8.6
通讯作者：
Li Shao-Chun
中科院分区：
文献类型：
--
作者：
Zhu Xin-Yang;Wang Shi;Jia Zhen-Yu;Zhu Li;Li Qi-Yuan;Zhao Wei-Min;Xue Cheng-Long;Xu Yong-Jie;Ma Zhen;Wen Jinsheng;Yu Shun-Li;Li Jian-Xin;Li Shao-Chun
的金属化通常在电荷密度波（CDW）的畴边界处开始，以牺牲其长程有序为代价。然而，在这项研究中，我们表明，金属化的也可以实现不打破表面碱掺杂后的长程CDW秩序。通过使用扫描隧道显微镜，我们发现的长程CDW秩序总是持久的，而金属化，而不是与额外的间隙激发。有趣的是，在间隙激发的顶部附近的较低的哈伯德带，在传统的电子掺杂的莫特绝缘体的哈伯德带下面。结合数值计算，我们认为，在Hubbard能带附近出现的隙内激发主要是由于吸附的碱金属离子有效地降低了在位库仑能.
Metallization ofis generally initiated at the domain boundary of a charge density wave (CDW), at the expense of its long-range order. However, we demonstrate in this study that the metallization ofcan 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.