{
  "id": "cond-mat/0510062",
  "version": "v1",
  "published": "2005-10-04T03:01:28.000Z",
  "updated": "2005-10-04T03:01:28.000Z",
  "title": "Two-probe theory of scanning tunneling microscopy of single molecules: Zn(II)-etioporphyrin on alumina",
  "authors": [
    "John Buker",
    "George Kirczenow"
  ],
  "comment": "Physical Review B, in press",
  "doi": "10.1103/PhysRevB.72.205338",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "We explore theoretically the scanning tunneling microscopy of single molecules on substrates using a framework of two local probes. This framework is appropriate for studying electron flow in tip/molecule/substrate systems where a thin insulating layer between the molecule and a conducting substrate transmits electrons non-uniformly and thus confines electron transmission between the molecule and substrate laterally to a nanoscale region significantly smaller in size than the molecule. The tip-molecule coupling and molecule-substrate coupling are treated on the same footing, as local probes to the molecule, with electron flow modelled using the Lippmann-Schwinger Green function scattering technique. STM images are simulated for various positions of the stationary (substrate) probe below a Zn(II)-etioporphyrin I molecule. We find that these images have a strong dependence on the substrate probe position, indicating that electron flow can depend strongly on both tip position and the location of the dominant molecule-substrate coupling. Differences in the STM images are explained in terms of the molecular orbitals that mediate electron flow in each case. Recent experimental results, showing STM topographs of Zn(II)-etioporphyrin I on alumina/NiAl(110) to be strongly dependent on which individual molecule on the substrate is being probed, are explained using this model. A further experimental test of the model is also proposed.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2005-10-04T03:01:28.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "scanning tunneling microscopy",
      "single molecules",
      "two-probe theory",
      "electron flow",
      "substrate transmits electrons"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Phys. Rev. B"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}