Field regulation of single-molecule conductivity by a charged surface atom

Electrical transport through molecules has been much studied since it was proposed that individual molecules might behave like basic electronic devices, and intriguing single-molecule electronic effects have been demonstrated. But because transport properties are sensitive to structural variations on the atomic scale, further progress calls for detailed knowledge of how the functional properties of molecules depend on structural features. The characterization of two-terminal structures has become increasingly robust and reproducible, and for some systems detailed structural characterization of molecules on electrodes or insulators is available. Here we present scanning tunnelling microscopy observations and classical electrostatic and quantum mechanical modelling results that show that the electrostatic field emanating from a fixed point charge regulates the conductivity of nearby substrate-bound molecules. We find that the onset of molecular conduction is shifted by changing the charge state of a silicon surface atom, or by varying the spatial relationship between the molecule and that charged centre. Because the shifting results in conductivity changes of substantial magnitude, these effects are easily observed at room temperature.

[1]  Eamonn F. Healy,et al.  Development and use of quantum mechanical molecular models. 76. AM1: a new general purpose quantum mechanical molecular model , 1985 .

[2]  G. Nazin,et al.  Visualization and Spectroscopy of a Metal-Molecule-Metal Bridge , 2003, Science.

[3]  Role of heating and current-induced forces in the stability of atomic wires , 2004, cond-mat/0409772.

[4]  H. Grubin.  The physics of semiconductor devices , 1979, IEEE Journal of Quantum Electronics.

[5]  G. Herzberg.  Atomic Spectra and Atomic Structure , 1937 .

[6]  Harold Basch,et al.  Compact effective potentials and efficient shared‐exponent basis sets for the first‐ and second‐row atoms , 1984 .

[7]  Christian Joachim,et al.  Probing the different stages in contacting a single molecular wire. , 2003, Physical review letters.

[8]  Hong Guo,et al.  Momentum filtering effect in molecular wires , 2004 .

[9]  C. Joachim,et al.  Molecules on insulating films: scanning-tunneling microscopy imaging of individual molecular orbitals. , 2005, Physical review letters.

[10]  Jonas I. Goldsmith,et al.  Coulomb blockade and the Kondo effect in single-atom transistors , 2002, Nature.

[11]  Supriyo Datta,et al.  Current-voltage characteristics of molecular conductors: two versus three terminal , 2002 .

[12]  James M Tour,et al.  Effect of local environment on molecular conduction: isolated molecule versus self-assembled monolayer. , 2005, Nano letters.

[13]  C. Joachim,et al.  Controlled manipulation of a single molecular wire along a copper atomic nanostructure , 2004 .

[14]  K. Rieder,et al.  Transport limitations in tunneling spectroscopy of Ge ( 111 ) c ( 2 × 8 ) surfaces , 2004 .

[15]  G. Baffou,et al.  Chemisorbed bistable molecule: Biphenyl on SiÑ100Ö-2ˆ1 , 2004 .

[16]  The smallest molecular switch. , 2003, Physical review letters.

[17]  John K. Tomfohr,et al.  Reproducible Measurement of Single-Molecule Conductivity , 2001, Science.

[18]  M. Reed,et al.  Conductance of a Molecular Junction , 1997 .

[19]  J. Gimzewski,et al.  An electromechanical amplifier using a single molecule , 1997 .

[20]  G. DiLabio,et al.  Dispersion interactions enable the self-directed growth of linear alkane nanostructures covalently bound to silicon. , 2004, Journal of the American Chemical Society.

[21]  G. Scuseria,et al.  Gaussian 03, Revision E.01. , 2007 .

[22]  Jean-Luc Brédas,et al.  Single-electron transistor of a single organic molecule with access to several redox states , 2003, Nature.

[23]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[24]  G. Lopinski,et al.  Self-directed growth of molecular nanostructures on silicon , 2000, Nature.

[25]  D. Hamann,et al.  Theory and Application for the Scanning Tunneling Microscope , 1983 .

[26]  J. Pitters,et al.  Protection-deprotection chemistry to control styrene self-directed line growth on hydrogen-terminated Si(100). , 2005, Journal of the American Chemical Society.

[27]  A. Daniel Boese,et al.  A new parametrization of exchange–correlation generalized gradient approximation functionals , 2001 .

[28]  John Bardeen,et al.  Surface States and Rectification at a Metal Semi-Conductor Contact , 1947 .

[29]  C. Daniel Frisbie,et al.  Distance Dependence of Electron Tunneling through Self-Assembled Monolayers Measured by Conducting Probe Atomic Force Microscopy: Unsaturated versus Saturated Molecular Junctions , 2002 .