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Significant negative differential resistance predicted in scanning tunneling spectroscopy for a C60 monolayer on a metal surface
Physical Review B - Condensed Matter and Materials Physics (2009)
  • X.Q. Shi, Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR, China
  • Woei Wu Pai, Center for Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan
  • X.D. Xiao, Department of Physics, Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
  • J.I. Cerdá, Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Cantoblanco, 28049 Madrid, Spain
  • R.Q. Zhang, Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China
  • C. Minot, Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China
  • M.A. Van Hove, Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR, China
Abstract
We theoretically predict the occurrence of negative differential resistance (NDR) in scanning tunneling spectroscopy (STS) for a pure C60 monolayer deposited on a metal surface using metal tips, namely on a Cu(111) surface and using various W tips. It is proposed that the likely reason why NDR has not been observed under such conditions is that NDR can be reduced if an oxidized or Cu-terminated tip is used. A detailed decomposition of the total tunneling current into its contributions from individual molecular orbitals reveals that only some of the orbitals on the tip and on the C60 can be “matched up” to give a contribution to the current and that the NDR is a consequence of the mismatch between these specific orbitals within particular ranges of bias voltage. Moreover, the NDR characteristics, including the peak positions and the peak-to-valley ratios, are found to depend on the tip material, tip geometry, and tip-to-molecule position.
Disciplines
Publication Date
2009
DOI
10.1103/PhysRevB.80.075403
Publisher Statement
Publisher version is archived on this website.
Citation Information
X.Q. Shi, Woei Wu Pai, X.D. Xiao, J.I. Cerdá, et al.. "Significant negative differential resistance predicted in scanning tunneling spectroscopy for a C60 monolayer on a metal surface" Physical Review B - Condensed Matter and Materials Physics Vol. 80 Iss. 7 (2009) p. 075403-1 - 075403-6 ISSN: 1550235X
Available at: http://works.bepress.com/mavanhove/94/