Scanning tunneling microscopy: A chemical perspective

C. J. Chen, M. Tsukada, V. T. Binh, S. M. Lindsay

Research output: Contribution to journalReview articlepeer-review

7 Scopus citations

Abstract

In this review article, scanning tunneling microscopy (STM) is presented in a chemical perspective. The typical distance from the nucleus of the apex atom of the tip to the top-layer nuclei of the sample is 4-6 Å, where a strong attractive atomic force, i.e., a partial covalent bond, arises between the tip and the sample. The origin of the covalent bond is the back-and- forth transfer of electrons between two atoms, which Pauling has called resonance. While a bias voltage is applied between them, a net electron current in a specific direction arises. This tunneling current is a result of the overlap of the tip electronic state and the sample electronic state, same as the chemical bond. The imaging process of STM can be considered as a sequence of local bond forming and bond rupturing. A quantitative understanding of the STM imaging mechanism can be achieved in such a chemical perspective. A natural consequence of this perspective is that the tip, partially bonded with the sample, can play an active role in local chemical reactions. The tip can either involve directly in a chemical reaction with the atoms on the sample surface or induce local chemical reactions on the sample surface as a local catalyst.

Original languageEnglish (US)
Pages (from-to)793-804
Number of pages12
JournalScanning Microscopy
Volume7
Issue number3
StatePublished - Sep 1 1993
Externally publishedYes

Keywords

  • Scanning tunneling microscopy
  • atomic force microscopy
  • chemical bond

ASJC Scopus subject areas

  • Instrumentation

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