Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 62: Frontiers of Electronic Structure Theory: Focus on Topology and Transport III
O 62.7: Talk
Wednesday, March 9, 2016, 17:00–17:15, H24
Steady-State Density Functional Theory for Finite Bias Conductances — •Stefan Kurth1,2 and Gianluca Stefanucci3,4 — 1Dept. of Materials Physics, Univ. of the Basque Country UPV/EHU, San Sebastian, Spain — 2IKERBASQUE, Basque Foundation for Science, Bilbao, Spain — 3Dept. of Physics, Univ. of Rome "Tor Vergata", Rome, Italy — 4INFN, Frascati, Italy
In the framework of density functional theory a formalism to describe electronic transport in the steady state is proposed which uses the density on the junction and the steady current as basic variables. In a finite window around zero bias, a one-to-one map is established between the basic variables and both local potential on as well as bias across the junction. The resulting Kohn-Sham system features two exchange-correlation (xc) potentials, a local xc potential and an xc contribution to the bias. For weakly coupled junctions the xc potentials exhibit steps in the density-current plane which are shown to be crucial to describe the Coulomb blockade diamonds. At small currents these steps emerge as the equilibrium xc discontinuity bifurcates. The formalism is applied to a model benzene junction, finding perfect agreement with the orthodox theory of Coulomb blockade.