Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 28: Electronic Structure Theory: General I

O 28.6: Vortrag

Dienstag, 13. März 2018, 11:45–12:00, MA 141

Calculation of molecular conductance "on the fly" for thousands of junction geometries — •Hector Vazquez — Inst. of Physics, Academy of Sciences of the Czech Rep., CZ

Single molecule circuits, where an electrical current is passed across a molecule placed between two electrodes, are ideal systems for studying a range of quantum phenomena[1]. Ab-initio transport calculations based on DFT-NEGF give a detailed description of transmission but their computational cost restricts this approach to a few structures.

In this talk I will describe an approximate method to calculate molecular conductance from a small cluster including the molecule. The reduced computational cost of this approximation enables the calculation of thousands of junction structures. When combined with Molecular Dynamics simulations, the evolution of junction structure and conductance can be simultaneously calculated. I will discuss this approximation to conductance and its implementation in the SIESTA code[2]. I will present results for several conjugated systems for tens of thousands of geometries[3] and analyze the relationship between molecular structure and conductance.

[1] T.A. Su, M. Neupane, M.L. Steigerwald, L. Venkataraman and C. Nuckolls, Nature Rev. Mater. 1 16002 (2016).

[2] J.M. Soler, E. Artacho, J.D. Gale, A. Garcia, J. Junquera, P. Ordejon, and D. Sanchez-Portal, J. Phys. Cond. Matt. 14, 2745 (2002).

[3] H. Vazquez, R. Skouta, S. Schneebeli, M. Kamenetska, R.Breslow, L. Venkataraman and M.S. Hybertsen, Nature Nanotechnol. 7 663 (2012).