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TT: Fachverband Tiefe Temperaturen

TT 75: Poster Session: Transport 1

TT 75.18: Poster

Donnerstag, 23. März 2017, 15:00–19:00, P2-EG

Ab-initio Simulation of Quantum Transport through Silane Molecular Wires — •María Camarasa-Gómez¹, Haixing Li², Daniel Hernangómez-Pérez¹, Latha Venkataraman², and Ferdinand Evers¹ — ¹Institute of Theoretical Physics, University of Regensburg, D-93050 Regensburg, Germany — ²Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States

The transport properties of molecular wires are sensitive to the relative alignment of the energies of the molecular orbitals and the Fermi-energy of the contact electrodes. A natural expectation is that the alignment shifts when one contact material, e.g., Au is replaced by another material, e.g., Ag; to lowest order, the shift should reflect the difference in the work functions [1]. We have performed an elaborate set of ab-initio transport calculations that puts this hypothesis to a test.

Motivated by recent experiments, we adopt a silane molecular wire as a paradigm system. We calculate the transmission function for Au and Ag substrates, for thiol- and amino- anchor groups [2] and a variety of different contact geometries. While our results qualitatively confirm the original hypothesis, we also observe other electrode related mechanisms that appear to be of similar magnitude compared to the work function shift. Our theoretical analysis will be compared to experimental data.

[1] T. Kim et al., NanoLett. 13, 3358 (2013)

[2] Y. Kim et al., ACS Nano 5, 4104 (2011)