Article abstract


Nature Materials 7, 68 - 74 (2008)
Published online: 25 November 2007 | doi:10.1038/nmat2060

Subject Categories: Biological materials | Electronic materials | Nanoscale materials

Electronic structure of single DNA molecules resolved by transverse scanning tunnelling spectroscopy

Errez Shapir1, Hezy Cohen1, Arrigo Calzolari2, Carlo Cavazzoni2,3, Dmitry A. Ryndyk4, Gianaurelio Cuniberti4,6, Alexander Kotlyar5, Rosa Di Felice2 & Danny Porath1


Attempts to resolve the energy-level structure of single DNA molecules by scanning tunnelling spectroscopy span over the past two decades, owing to the unique ability of this technique to probe the local density of states of objects deposited on a surface. Nevertheless, success was hindered by extreme technical difficulties in stable deposition and reproducibility. Here, by using scanning tunnelling spectroscopy at cryogenic temperature, we disclose the energy spectrum of poly(G)–poly(C) DNA molecules deposited on gold. The tunnelling current–voltage (IV) characteristics and their derivative (dI/dVV) curves at 78 K exhibit a clear gap and a peak structure around the gap. Limited fluctuations in the IV curves are observed and statistically characterized. By means of ab initio density functional theory calculations, the character of the observed peaks is generally assigned to groups of orbitals originating from the different molecular components, namely the nucleobases, the backbone and the counterions.

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  1. Physical Chemistry Department and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel
  2. National Center on nanoStructures and bioSystems at Surfaces (S3) of INFM-CNR, Via Campi 213/A, 41100 Modena, Italy
  3. CINECA, Via Magnanelli 6/3, 40033 Casalecchio di Reno Bologna, Italy
  4. Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany
  5. Department of Biochemistry George S. Wise Faculty of Life Sciences and Nanotechnology Center Tel Aviv University, Ramat Aviv 69978, Israel
  6. Present address: Institute for Materials Science and Max Bergmann Center for Biomaterials, Dresden University of Technology, D-01069 Dresden, Germany

Correspondence to: Rosa Di Felice2 e-mail: rosa@unimore.it

Correspondence to: Danny Porath1 e-mail: porath@chem.ch.huji.ac.il



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