Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 15: Focus Session: Frontiers of Electronic Structure Theory - Non-Equilibrium Phenomena at the Nano-Scale (organized by O)

TT 15.2: Talk

Monday, March 31, 2014, 11:00–11:15, TRE Ma

On the description of biased nanocontacts from ab initio — •Steven Achilles¹, Jürgen Henk¹, Michael Czerner², Christian Heiliger², and Ingrid Mertig¹ — ¹Institute of Physics, Martin Luther University Halle-Wittenberg, D-06099 Halle, Germany — ²I. Physikalisches Institut, Justus Liebig University, D-35392 Giessen, Germany

A suitable description of arbitrary shaped and biased nanocontacts is very important for investigating and predicting physical effects of materials on the nanometer scale. In particular, the electronic transport properties under finite bias voltages are of great interest.

To account for systems under finite bias we extended our Korringa-Kohn-Rostoker Green’s function method [1] to the Keldysh formalism [2]. The method was developed for different types of geometries, i.e. planar junctions [3] and embedded real-space clusters [4]. Both implementations include a self-consistent treatment of the electronic structure under external bias using the nonequilibrium density.

We present ab initio results of voltage drops, the charge relaxation under finite bias voltage and current-voltage characteristics for different types of geometries.

[1] R. Zeller, P.H. Dederichs, B. Ujfalussy, L. Szunyogh, and P. Weinberger, Phys. Rev. B 52, 8807 (1995).; P. Zahn, I. Mertig, R. Zeller, and P.H. Dederichs, Mat. Res. Soc. Symp. Proc. 475, 525 (1997).

[2] L.V. Keldysh, Sov. Phys. JETP 20 (4), 1018-1026 (1965).

[3] S. Achilles et al., Phys. Rev. B 88 (12), 125411 (2013).

[4] S. Achilles et al., to be published