Berlin 2008 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 29: Poster II

DY 29.71: Poster

Donnerstag, 28. Februar 2008, 16:00–18:00, Poster C

Nonlinear ion transport and resulting jump pathways in disordered systems — •Lars Lühning and Andreas Heuer — Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Germany

The nonlinear conductivity effects of thin ionic conductors under the influence of ac- and dc electric fields are studied numerically and analytically using a regular single particle hopping model which contains a characteristic hopping distance between adjacent sites. The transition rates are deduced from different kinds of distributions of the trapping sites using periodic boundary conditions.

An analytical expression for the stationary current densities under a constant field in one dimension is presented and verified by numerical simulations. It turns out that the stationary current densities depend on the sample thickness and, interestingly, the first correction to the linear response display a non-analytical behaviour in the thermodynamic limit.

Numerical calculations of the current densities are expanded both to the ac regime and to two dimensional systems and compared with experimental results. In two dimensions possibly resulting jump pathways due to a percolation approach are also presented.

Furthermore, transition rates are extracted from three dimensional hopping dynamics analyzed by molecular dynamics simulations.