Article Title

Direct imaging of molecular orbitals of metal phthalocyanines on metal surfaces with an O₂-functionalized tip of a scanning tunneling microscope

Authors

Zhihai Cheng, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
Shixuan Du, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
Wei Guo, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
Li Gao, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
Zhitao Deng, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
Nan Jiang, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
Haiming Guo, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
Hao Tang, Center for Material Elaboration and Structural Studies, B.P. 94347, 31055 Toulouse Cedex, France
H. -J. Gao, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China

Keywords

High-resolution scanning tunneling microscope (STM) imaging, functionalized STM tip, metal phthalocyanines, molecular orbital, density functional theory calculation

Abstract

High-resolution scanning tunneling microscope images of iron phthalocyanine and zinc phthalocyanine molecules on Au(111) have been obtained using a functionalized tip of a scanning tunneling microscope (STM), and show rich intramolecular features that are not observed using clean tips. Ab initio density functional theory calculations and extended Hückel theory calculations revealed that the imaging of detailed electronic states is due specifically to the decoration of the STM tip with O2. The detailed structures are differentiated only when interacting with the highly directional orbitals of the oxygen molecules adsorbed on a truncated, [111]-oriented tungsten tip. Our results indicate a method for increasing the resolution in generic scans and thus, have potential applications in fundamental research based on high-resolution electronic states of molecules on metals, concerning, for example, chemical reactions, and catalysis mechanisms.

Graphical Abstract

DOI

https://doi.org/10.1007/s12274-011-0108-y

Publisher

Tsinghua University Press

Recommended Citation

Zhihai Cheng,Shixuan Du,Wei Guo,Li Gao,Zhitao Deng,Nan Jiang,Haiming Guo,Hao Tang,H. -J. Gao, Direct imaging of molecular orbitals of metal phthalocyanines on metal surfaces with an O2-functionalized tip of a scanning tunneling microscope. NanoRes.2011, 4(6): 523–530