cfaed Seminar Series

Dr. Hector Vazquez , Institute of Physics, Academy of Sciences of the Czech Republic

Tuning elastic and inelastic electron transport across single molecule circuits

06.07.2017 (Thursday) , 13:00 - 14:00
TU Dresden, HAL, Seminar Room 115 , Hallwachsstr. 3 , 01069 Dresden

About the talk

Single molecule circuits are ideal systems for studying a wide range of quantum phenomena [1]. The flow of an electric current across individual molecules placed between metal electrodes is determined by the junction electronic structure, which in turn is strongly affected by both the nature of the molecular backbone and the metalmolecule links. Calculations based on Density-Functional Theory and non- Equilibrium Green’s Functions can be used to understand and predict the
conductance of molecular nanostructures.

I will start by discussing elastic transport focusing on the coupling between metal and molecule [2]. I will compare the signature in conductance of different Au-molecule links and examine their behaviour under an applied bias. I will then turn to the other main ‘component’ of the circuit: the molecular backbone. Backbone properties, often with no classical equivalent, can bring important consequences for conductance [3,4].

The second part of my talk will address our recent work on the interaction of electronic and vibrational degrees of freedom. I will show how an analysis of the different contributions which make up the inelastic peaks can completely characterize the formation of the inelastic signal [5]. I will also discuss the current-induced heating and cooling of the junction from the calculation of rates of absorption or emission of molecular vibrations by the tunneling electrons.

Bio

Hector Vazquez is a Purkyne Fellow and senior scientist at the Institute of Physics of the Academy of Sciences of the Czech Republic in Prague. Hector did his PhD at the Universidad Autonoma de Madrid. He enjoyed postdoctoral stays abroad with A.-P. Jauho and M. Brandbyge in Denmark, L. Venkataraman and M.S. Hybertsen in the US and A. Troisi in the UK. In Prague he started the Molecular Transport Group. He is interested in the electronic and conducting properties of
molecular nanostructures.

References

[1] J.C. Cuevas and E. Scheer, ‘Molecular Electronics: An Introduction to Theory and Experiment’, World Scientific Series in Nanotechnology and Nanoscience (2010).
[2] F. Schwarz and E. Loertscher, J. Phys. Condens. Matter 26 474201 (2014).
[3] H. Vázquez, R. Skouta, S. Schneebeli, M. Kamenetska, R.Breslow, L. Venkataraman and M.S. Hybertsen, Nat. Nanotechnol. 7 663 (2012).
[4] S. Fujii, S. Marqués-González, J.Y. Shin, H. Shinokubo, T. Masuda, T. Nishino, N.P. Arasu, H. Vázquez and M. Kiguchi, Nat. Commun. (in press)
[5] G. Foti and H. Vázquez, Phys. Rev. B 94 045418 (2016)

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