Invited talk

Charge and energy transport in atomic and molecular junctions

Fabian Pauly

Department of Physics, University of Konstanz, D-78457 Konstanz, Germany

Single-atom and single-molecule junctions represent the ultimate limit to the miniaturization of electrical circuits. They are also ideal platforms for testing quantum transport theories that are required to describe charge and energy transfer in novel functional nanometer-scale devices.

In this seminar, I will review the recent theoretical progress of my group towards the description of elastic and inelastic charge transport in atomic and molecular junctions as well as thermoelectric phenomena and heat dissipation. After a brief introduction, I will discuss results on the conductance [1,2], inelastic electron tunneling spectra [3,4] and the thermopower [5-8]. Next, I will show an ab-initio characterization of the thermoelectric figure of merit of molecular junctions including both electronic and phononic contributions to the thermal conductance [9]. Finally, I will present combined experimental and theoretical efforts to understand the heat dissipation in atomic-scale junctions [10,11].

[1] Influence of conformation on conductance of biphenyl-dithiol single-molecule contacts, A. Mishchenko, D. Vonlanthen, V. Meded, M. Bürkle, C. Li, I. V. Pobelov, A. Bagrets, J. K. Viljas, F. Pauly, F. Evers, M. Mayor, and T. Wandlowski, Nano Lett. 10, 156 (2010).

[2] Conduction mechanisms in biphenyl-dithiol single-molecule junctions, M. Bürkle, J. K. Viljas, A. Mishchenko, D. Vonlanthen, G. Schön, M. Mayor, T. Wandlowski, and F. Pauly, Phys. Rev. B 85, 075417 (2012).

[3] Influence of vibrations on electron transport through nanoscale contacts, M. Bürkle, J. K. Viljas, T. J. Hellmuth, E. Scheer, F. Weigend, G. Schön, F. Pauly, Phys. Status Solidi B 250, 2468 (2013).

[4] Identification of the current path for a conductive molecular wire on a tripodal platform, M. A. Karimi, S. G. Bahoosh, M. Valášek, M. Bürkle, M. Mayor, F. Pauly, and E. Scheer (submitted).

[5] Ab initio study of the thermopower of biphenyl-based single-molecule junctions, M. Bürkle, L. A. Zotti, J. K. Viljas, D. Vonlanthen, A. Mishchenko, T. Wandlowski, M. Mayor, G. Schön, F. Pauly, Phys. Rev. B 86, 115304 (2012).

[6] Length-dependent conductance and thermopower in single-molecule junctions of dithiolated oligophenylene derivatives, F. Pauly, J. K. Viljas, and J. C. Cuevas, Phys. Rev. B 78, 035315 (2008).

[7] Molecular dynamics study of the thermopower of Ag, Au, and Pt nanocontacts, F. Pauly, J. K. Viljas, M. Bürkle, M. Dreher, P. Nielaba, J. C. Cuevas, Phys. Rev. B 84, 195420 (2011).

[8] Quantum thermopower of metallic atomic-size contacts at room temperature, C. Evangeli, M. Matt, L. Rincón-García, F. Pauly, P. Nielaba, G. Rubio-Bollinger, J. C. Cuevas, N. Agraït, Nano Lett. 15, 1006 (2015).

[9] First principles calculation of the thermoelectric figure of merit for [2,2]paracyclophane-based single-molecule junctions, M. Bürkle, T. J. Hellmuth, F. Pauly, Y. Asai, Phys. Rev. B 91, 165419 (2015).

[10] Heat dissipation in atomic-scale junctions, W. Lee, K. Kim, W. Jeong, L. A. Zotti, F. Pauly, J. C. Cuevas, P. Reddy, Nature 498, 209 (2013).

[11] Heat dissipation and its relation to thermopower in single-molecule junctions, L. A. Zotti, M. Bürkle, F. Pauly, W. Lee, K. Kim, W. Jeong, Y. Asai, P. Reddy, and J. C. Cuevas, New J. Phys. 16, 015004 (2014).