12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Variable contact gap single-molecule conductanc...
View graph of relations

« Back

Variable contact gap single-molecule conductance determination for a series of conjugated molecular bridges

Research output: Contribution to journalJournal article

Published

  • Wolfgang Haiss
  • Changsheng Wang
  • Rukkiat Jitchati
  • Iain Grace
  • Santiago Martin
  • Andrei S. Batsanov
  • Simon J. Higgins
  • Martin R. Bryce
  • Colin J. Lambert
  • Palle S. Jensen
  • Richard J. Nichols
???articleNumber???374119
Journal publication date17/09/2008
JournalJournal of Physics: Condensed Matter
Journal number37
Volume20
Number of pages9
Pages-
Original languageEnglish

Abstract

It is now becoming clear that the characteristics of the whole junction are important in determining the conductance of single molecules bound between two metal contacts. This paper shows through measurements on a series of seven conjugated molecular bridges that contact separation is an important factor in determining the electrical response of the molecular junction. These data are obtained using the I (t) method developed by Haiss et al since the scanning tunnelling microscope tip to substrate separation can be controlled through choice of the set-point (I-0) current and calibrated with current-distance curves and knowledge of the terminal to terminal length of the molecular wire. The contact gap separation dependence is interpreted as arising from tilting of these molecules in the junction and this model is underpinned by ab initio transport computations. In this respect we make the general observation that conductance increases rather dramatically at higher tilt angle away from the normal for conformationally rigid molecular wires and that this increase in conductance arises from increased electronic coupling between the molecular bridge and the gold contacts.