A time-dependent momentum-space density functional theoretical approach for electron transport dynamics in molecular devices

We propose a time-dependent density functional theoretical (TDDFT) approach in momentum (P) space for the study of electron transport in molecular devices under arbitrary biases. The basic equation of motion, which is a time-dependent integrodifferential equation obtained by Fourier transform of the time-dependent Kohn-Sham equation in spatial coordinate (R) space, is formally exact and includes all the effects and information of the electron transport in the molecular devices. The electron wave function is calculated by solving this equation in a finite P-space volume. This approach is free of self-energy function and memory term related to the electrodes in the R space and beyond the wide-band limit (WBL). The feasibility and power of the approach are demonstrated by the calculation of current through one-dimensional systems. Copyright c EPLA, 2009