Charge Transfer, Phase Separation, and Mott–Hubbard Transition in Potassium-Doped Coronene Films

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• 作者：Xuefeng Wu ; Chaoqiang Xu ; Kedong Wang ; Xudong Xiao
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：July 21, 2016
• 年：2016
• 卷：120
• 期：28
• 页码：15446-15452
• 全文大小：456K
• 年卷期：0
• ISSN：1932-7455

文摘

Scanning tunneling microscopy and spectroscopy have been applied to study the pristine and potassium-doped coronene films at the molecular level with the doping ratio x ranging from 0 to 4. Both the morphology and the electronic property were found to be strongly governed by the amount of charge transfer. Certain phases of K₃Coronene and K₄Coronene could be fabricated at the corresponding K doping ratios. While in K₄Coronene a doubly degenerate LUMO state of the undoped coronene became fully occupied, in K₃Coronene that state was observed to cross the Fermi level and split into an upper unoccupied part and a lower occupied part, implying the presence of electronic correlation effect and Mott–Hubbard transition in the system. The observed four different phases of K₃Coronene further showed different strengths of electronic correlation effect and led us to speculate that the superconductivity transition with different T_c in potassium-doped coronene observed elsewhere might have an origin from the electronic correlation effect with different strengths.