An efficient molecular orbital approach for self-consistent calculations of molecular junctions.
To model electron transport through a molecular junction, we propose an efficient method using an ab initio self-consistent nonequilibrium Green's function theory combined with density functional theory. We have adopted a model close to the extended molecule approach, due to its flexibility, but have improved on the problems relating to molecule-surface couplings and the long-range potential via a systematic procedure for the same ab initio level as that of Green's function. The resulting algorithm involves three main steps: (i) construction of the embedding potential; (ii) perturbation expansion of Green's function in the molecular orbital basis; and (iii) truncation of the molecular orbital space by separating it into inactive, active, and virtual spaces. The above procedures directly reduce the matrix size of Green's function for the self-consistent calculation step, and thus, the algorithm is suitable for application to large molecular systems.
Nakamura
Hisao
H
Department of Chemical System Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan. nakamura@tcl.t.u-tokyo.ac.jp
Yamashita
Koichi
K