Atomic-scale control of molecular contacts

DIPC Seminars

Speaker

Guillaume Schull, Institut de Physique et Chimie des Matériaux de Strasbourg, France

When

2011/06/08
14:00

Place

Donostia International Physics Center (DIPC).Paseo Manuel de Lardizabal, 4 (nearby the Facultad de Quimica), Donostia

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Atomic-scale control of molecular contacts Guillaume Schull Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 (CNRS -- Université de Strasbourg), 67034 Strasbourg, France. [guillaume.schull@ipcms.u-strasbg.fr](mailto:guillaume.schull@ipcms.u-strasbg.fr) The transport of charge through a conducting material depends on the intrinsic ability of the material to conduct current and on the charge injection efficiency at the contacts between the conductor and the electrodes. Exploring the single molecule limit in experiments requires control of the junction geometry. Scanning tunneling microscopy (STM) provides here a way to probe this parameter with atomic scale precision. We will see that the current passing through a single molecule can be probed while changing, one by one, the number of atoms in the electrode in contact with a single molecule [1]. For C60, this revealed a crossover from a regime in which the conductance is limited by scattering at the molecule to a regime in which the conductance is limited by charge injection at the contact with a sharp electrode. In the case of a single atom contact between molecule and electrode, we will see that the efficiency of charge injection depends strongly on where the molecule is contacted [2]. In a last step, the transport properties of small chains made of two C60 trapped between the tip and the surface of a STM will be presented [3]. The experimental results are complemented by first-principles transport calculations which give access to the geometry-dependent nature of the junctions’ properties. [1] Schull G, Frederiksen T, Arnau A, Sanchez-Portal D, Berndt R. Nature Nanotec. 6, (2011) 23 [2] Schull G, Dappe Y, Gonzalez C, Bulou H, Berndt R. Submitted. [3] Schull G, Frederiksen T, Brandbyge M, Berndt R. Phys. Rev. Lett. 103, (2009) 206803