Simulation of scanning tunneling microscope images of 1,3-cyclohexadiene bound to a silicon surface.

Journal Article (Journal Article)

Scanning tunneling microscope (STM) images of 1,3-cyclohexadiene bound to silicon are interpreted using a nonequilibrium Green's function method. The resolution of the carbon-carbon double bond for positive bias voltages but not for negative bias voltages is explained using a quasiprobability density analysis. The asymmetry in the images arises from the system's voltage dependent electronic structure. A pi* orbital is found to be responsible for the empty state STM images of the carbon-carbon double bond, which is observed experimentally. The pi orbital relevant for the opposite bias does not produce an STM image sharply localized in the bond region because the molecule induces a Si-surface dipole dependent on the bias. The dipole voltage dependence arises from molecular charging. This result emphasizes the importance of simulating the molecule as an element in an open quantum system.

Full Text

Duke Authors

Cited Authors

  • Galperin, M; Beratan, DN

Published Date

  • February 2005

Published In

Volume / Issue

  • 109 / 4

Start / End Page

  • 1473 - 1480

PubMed ID

  • 16851118

Electronic International Standard Serial Number (EISSN)

  • 1520-5207

International Standard Serial Number (ISSN)

  • 1520-6106

Digital Object Identifier (DOI)

  • 10.1021/jp045783f


  • eng