1. P. Grutter Making Contact to Molecules: Interfacing to the Nanoworld Peter Grutter Physics Department McGill University NSERC, FCAR, CIAR, McGill, IBM, CIHR, GenomeQuebec, CFI, NanoQuebec

2. P. Grutter What is Nanoelectronics?

3. P. Grutter What is Electronics? By electronics we mean the handling of complicated electrical wave forms for communicating information, probing (such as in radar) and data processing. Data processing is the result of one complex stream of information interacting with another. This requires non-linear behavior, otherwise information just gets passed on from one place to the other. (Landauer, Science 1968)

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6. Molecular electronics: the issues Contacts Structure-function relationship between transport process and molecular structure Dissipation Crosstalk (interconnects) Architecture I-O with a trillion processors Fault tolerance Manufacturing costs

7. P. Grutter Does atomic structure of the contact matter? YES !

8. P. Grutter Does atomic structure of the contact matter? Mehrez, Wlasenko, et al., Phys. Rev. B 65, 195419 (2002)

9. P. Grutter Comparison of Experimental and Modeling Results Mehrez, Wlasenko, et al., Phys. Rev. B 65, 195419 (2002)

10. P. Grutter ‘Traditional’: infinite, structureless leads -> periodic boundary conditions. but: - result depends on lead size! - bias not possible due to periodic boundary condition! Calculating Conductance Jellium lead molecule

11. P. Grutter Calculation of electrical transport

12. P. Grutter ab-initio modelling of electronic transport lead

13. P. Grutter DFT plus non-equilibrium Green’s Functions J. Taylor, H. Guo, J. Wang, PRB 63, R121104 (2001) 1. Calculate long, perfect lead. Apply external potential V by shifting energy levels -> create electrode data base and get potential  right lead

14. P. Grutter 2. Solve Poisson equation for middle part (device plus a bit of leads); match wavefunctions  and potential as a function of V to leads (use data base) in real space. 3.  calculated with non-equilibrium Green’s functions (necessary as this is an open system). This automatically takes care of bound states

15. P. Grutter Molecular electronics: the issues Contacts Structure-function relationship between transport process and molecular structure Dissipation Crosstalk (interconnects) Architecture I-O with a trillion processors Fault tolerance Manufacturing costs

16. P. Grutter Reliable, chemically well defined contacts Cui et al. Nanotechnology 13, 5 (2002), Science 294, 571 (2001)

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18. Low-T UHV STM/AFM/FIM 140K, 10 -11 mbar quick change between FIM - AFM/STM mode Stalder, Ph.D. Thesis 1995 Cross et al. PRL 80, 4685 (1998) Schirmeisen et al. NJP 2, 29.1 (2000)

19. P. Grutter Field Ion Microscopy (FIM) E. Muller, 1950’s

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21. FIM of W(111) tip Imaging at 5.0 kV

22. P. Grutter FIM of W(111) tip Imaging at 5.0 kV Manipulating at 6.0 kV

23. P. Grutter FIM of W(111) tip Imaging at 5.0 kV Manipulating at 6.0 kV

24. P. Grutter FIM of W(111) tip Imaging at 5.0 kV Manipulating at 6.0 kV

25. P. Grutter Single Au atom on W(111) tip Imaged at 2.1 KV

26. P. Grutter W(111) tip on Au(111) Cross et al. PRL 80, 4685 (1998) Schirmeisen et al, NJP 2, 29.1 (2000 )

27. P. Grutter Molecular Dynamics Simulations U. Landman et al, Science 248, 454 (1990)

28. P. Grutter W(111) trimer tip on Au(111) E ad = 21 eV  = 0.2 nm

29. P. Grutter Tip relaxation effects Hofer, Fisher, Wolkow and Grutter Phys. Rev. Lett. 87, 236104 (2001) W tip on Au(111) surface

30. P. Grutter Tip relaxation effects Hofer, Fisher, Wolkow and Grutter Phys. Rev. Lett. 87, 236104 (2001) W tip on Au(111) surface

31. P. Grutter F(z) and I(z) of W(111) trimer on Au(111) Schirmeisen et al, NJP 2, 29.1 (2000 )

32. P. Grutter Yan Sun, Anne-Sophie Lucier Henrik Mortensen

33. P. Grutter The samples (measurements in progress) A) Au(111) 170 nm×170 nm, B) mixture of C6 and C8 thiol (ratio 6:1) on Au(111) 450nm×450nm C) C8 thiol, 6nm×6nm D) C8/C8 dithiol 36nm×36 nm.

34. P. Grutter Stimulation of Single Ligand-Gated Ion Channels Natural Process: Synaptic Transmission Goal: To study channel gating kinetics and binding forces, while maintaining precise control of agonist location. Experiment: Ligand-functionalized AFM tip

35. P. Grutter N. Cameron, B. Lennox (McGill) Tethering Scheme: GABA v.s. GABOB Is it possible to tether a molecule of GABA without destroying its functionality?

36. P. Grutter Tethering Scheme: Polymer Linker Au -S-(CH 2 ) 12 -(O-CH 2 -CH 2 ) 23 -O-GABOB {alkanethiol} {PEO} Colloid simulates the AFM tip Keeps the colloid complex soluble (?)

37. P. Grutter Planar Patch-Clamp Chips Advanced microstructuring techniques are used to produce apertures in planar glass or quartz substrates. Low noise recordings have been realized from both artificial lipid bilayers and whole cells. Fertig et. al. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 2001 Oct;64(4-1):040901.

38. P. Grutter Loading Rate Dependent Unbinding: Most probable unbinding force: Ligand-receptor dissociation forces and rates depend on the rate at which the bond is ruptured!!! Distinct binding states can be identified from a force v.s. loading rate plot. Good review: Evans, E. Annu. Rev. Biophys. Biomol. Struct. 2001. 30:105-28.

39. P. Grutter F(z) as a function of pulling speed Clausen-Schaumann et al., Current Opinions in Chem. Biol. 4, 524 (2000) Merkel et al., Nature 397, (1999) Allows the determination of energy barriers and thus is a direct measure of the energy landscape in conformational space. Evans, Annu. Rev. Biophys. Biomol. Struct., 30, 105 (2001)

40. P. Grutter Summary Tools, both experimental and theoretical, drive our capabilities to understand the nanoworld! We develop and apply SPM techniques to interface to: molecules and neurons in order to understand structure - property relationships

41. P. Grutter Supported by NSERC, FCAR, CIAR, NanoQuebec CFI, IBM, GenomeQuebec, CIHR McGill Dawson Scholarship 14 graduate students, 6 post doctoral fellows