Observations of abundant structural and electronic phases in potassium-doped single-layer p-quaterphenyl film

作     者：Wei Chen MingQiang Ren Tong Zhang YaJun Yan DongLai Feng Wei Chen;MingQiang Ren;Tong Zhang;YaJun Yan;DongLai Feng

作者机构：23 Slate Key Laboratory of Surface PhysicsDepartmen1 of PhysicsFudan UniversityShanghai 200433China Hefei National Laboratory for Physical Sciences at the MicroscaleDepartment of PhysicsUniversity of Science and Technologv of ChinaHefei 230026China Collaborative Innovation Cener of Advanced MicosructuresNanjing 210093China 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2021年第64卷第5期

页      面：54-62页

核心收录：

学科分类：07[理学] 0809[工学-电子科学与技术（可授工学、理学学位）] 070205[理学-凝聚态物理] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0704[理学-天文学] 0702[理学-物理学] 

基　　金：supported by the National Natural Science Foundation of China(Grant No.11774060) the National Key R&D Program of the MOST of China(Grant Nos.2016YFA0300200,2017YFA0303004,2017YFA0303104,2016YFA0302300,and 2017YFA0303003) the National Basic Research Program of China(Grant No.2015CB921700) the Science Challenge Project(Grant No.TZ2016004) the Shanghai Education Development Foundation and Shanghai Municipal Education Commission(Chenguang Program) 

主　　题：scanning tunneling microscopy phenyl-based molecular film electronic correlation electron-vibration coupling Kondo effect 

摘      要：Scanning tunneling microscopy/spectroscopy is applied herein to study the pristine and potassium(K)-doped single-layer pquaterphenyl(P4P) films grown on the Au(111) substrate at the molecular level. Abundant complex structural and electronic phases are induced by various K doping. The Fermi-level pinning effect is observed at a low doping level. On the contrary,K3P4P exhibits intriguing versatile phases and properties because charge carriers are effectively doped in. For example, two kinds of molecular vibration modes with energies below 100 meV are observed, indicating a possible strong electron-phonon coupling. The splitting of the lowest unoccupied molecular orbital state in K3P4P illustrates an electronic correlation effect, and its strength varies for four different K3P4P phases with different structures. In addition, the appearance of a Kondo resonance on the molecular vacancy/impurity implies a local molecular magnetic moment. Our results demonstrate that the complex electronic properties of an alkali metal-doped P4P/Au film stem from the existence of many competing interactions, such as electronelectron correlations and electron-vibration coupling, which can be effectively tuned via variable carrier doping and molecular structure. Our work also opens new routes toward engineering novel molecular devices and creating new electronic phases in strongly correlated molecular materials.