Effective bias and potentials in steady-state quantum transport: A NEGF reverse-engineering study

Progress in Non-equilibrium Green's Functions

Karlsson, Daniel^1 ; Verdozzi, Claudio^2,3

Department of Physics, Nanoscience Center, University of Jyväskylä, P.O.Box 35, Jyväskylä

FI-40014, Finland^1

Department of Physics, Division of Mathematical Physics, Lund University, Lund

22100, Sweden^2

European Theoretical Spectroscopy Facility (ETSF), Finland^3

关键词: Effective potentials;    Exchange correlations;    Interaction strength;    Many body perturbation theory;    Non-equilibrium Green's function;    Non-interacting system;    Partitioned systems;    Steady-state density;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/696/1/012018/pdf
DOI  :  10.1088/1742-6596/696/1/012018

来源: IOP

【 摘 要 】

Using non-equilibrium Green's functions combined with many-body perturbation theory, we have calculated steady-state densities and currents through short interacting chains subject to a finite electric bias. By using a steady-state reverse-engineering procedure, the effective potential and bias which reproduce such densities and currents in a non-interacting system have been determined. The role of the effective bias is characterised with the aid of the so-called exchange-correlation bias, recently introduced in a steady-state density-functional- theory formulation for partitioned systems. We find that the effective bias (or, equivalently, the exchange-correlation bias) depends strongly on the interaction strength and the length of the central (chain) region. Moreover, it is rather sensitive to the level of many-body approximation used. Our study shows the importance of the effective/exchange-correlation bias out of equilibrium, thereby offering hints on how to improve the description of density- functional-theory based approaches to quantum transport.