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Rubidium-induced phase transitions among metallic, band-insulating, Mott-insulating phases in 1T-TaS2
Zhengguo Wang(王政国), Weiliang Yao(姚伟良), Yudi Wang(王宇迪), Ziming Xin(信子鸣), Tingting Han(韩婷婷), Lei Chen(陈磊), Yi Ou(欧仪), Yu Zhu(朱玉), Cong Cai(蔡淙), Yuan Li(李源), and Yan Zhang(张焱)
Chin. Phys. B,
2023, 32 (10):
107404.
DOI: 10.1088/1674-1056/acec40
Realizing phase transitions via non-thermal sample manipulations is important not only for applications, but also for uncovering the underlying physics. Here, we report on the discovery of two distinct metal-insulator transitions in 1T-TaS2 via angle-resolved photoemission spectroscopy and in-situ rubidium deposition. At 205 K, the rubidium deposition drives a normal metal-insulator transition via filling electrons into the conduction band. While at 225 K, however, the rubidium deposition drives a bandwidth-controlled Mott transition as characterized by a rapid collapsing of Mott gap and a loss of spectral weight of the lower Hubbard band. Our result, from a doping-controlled perspective, succeeds in distinguishing the metallic, band-insulating, and Mott-insulating phases of 1T-TaS2, manifesting a delicate balance among the electron-itineracy, interlayer-coupling and Coulomb repulsion. We also establish an effective method to tune the balance between these interactions, which is useful in seeking exotic electronic phases and designing functional phase-changing devices.
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