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Experimental characterization of simple single-molecule junctions

Experimental characterization of simple single-molecule junctions. In collaboration with. Kamerlingh Onnes Laboratory, Leiden University. Leiden: Marc van Hemert IBM Yorktown Heights: Norton Lang Technical University of Denmark: Kristian Thygesen, Karsten Jacobsen.

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Experimental characterization of simple single-molecule junctions

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  1. Experimental characterization of simple single-molecule junctions

  2. In collaboration with ... Kamerlingh Onnes Laboratory, Leiden University Leiden: Marc van Hemert IBM Yorktown Heights: Norton Lang Technical University of Denmark: Kristian Thygesen, Karsten Jacobsen. Darko Djukic Yves Noat Roel Smit Carlos Untiedt & JvR

  3. Mechanically Controllable Break Junction

  4. Mechanically Controllable Break Junction

  5. Conductance histogram for Au

  6. Conductance curve for Pt

  7. Conductance histogram for Pt

  8. Conductance curve for Pt/H2

  9. Conductance histogram for Pt/H2 Bias voltage 140 mV

  10. Principle of point contact spectroscopy G decreases for eV> ħω

  11. Point contact spectrum for Pt/H2 Modulation: 1 mV, 7 kHz Recording time: 10 s Temperature: 4.2 K

  12. Isotope shift

  13. Conductance fluctuations: 3 examples Au

  14. Principle of conductance fluctuationsin ballistic contacts

  15. RMS fluctuations measured for Au Gold Au

  16. Conductance fluctuations T = 0.97 (1) Smit et al., Nature 419, 906 (2002)

  17. More frequencies and stretching dependence

  18. K.S.Thygesen and K.W. Jacobsen (unpublished) New local density calculations

  19. Vibration modes of a Pt – H2 – Pt bridge

  20. Vibration modes for Deuterium, Pt–D2–Pt PtD2

  21. Vibration modes for Deuterium, Pt–D2–Pt PtD2

  22. PtD2 K.S.Thygesen and K.W. Jacobsen (unpublished)

  23. Comparison H2 and D2

  24. 2  Scaling of the modes by √m

  25. 2   3/2  Scaling of the modes by √m

  26. A test case for model calculations N. Lang (Nature 419 (2002) 906) . Conduction by antibonding orbitals. G = 0.9 G0. M.C. van Hemert, (Nature 419 (2002) 906) J. Kuipers and M.C. van Hemert, unpublished

  27. A test case for model calculations Y. Garcia, J.J. Palacios, et al., cond-mat/0310098 Conduction by bonding orbitals. ΔE=23eV. G = 0.2 G0.

  28. A test case for model calculations J. Heurich, F. Pauli, J.C. Cuevas, W. Wenzel and G. Schön, Nanotechnology 14 (2003) R29. Conduction by bonding orbitals. ΔE = 24eV. G = 0.86 G0

  29. A test case for model calculations K. Thygesen and K.W. Jacobsen, unpublished. Conduction by antibonding orbitals. ΔE = 10-13 eV. G = 1.0 G0

  30. CO and Pt (preliminary)

  31. Conclusions • Molecular hydrogen forms a nearly ideal conductor when placed between Pt electrodes, despite the closed-shell character of the free molecule. • Single-molecule junctions can be characterized by the vibration modes, their stretching dependence, by the conductance and by the number of conduction channels. • Hydrogen forms a good test-case for model calculations. • More work on larger organic molecules … Universiteit Leiden

  32. Switching behavior for HD

  33. Switching during stretching PtHD puzzle

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