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Time-Dependent Density Functional Theory with Ultrasoft Pseudopotential: Real-Time Electron Propagation across Molecular Junction

Xiaofeng Qian·Ju Li·Xi Lin·Sidney Yip
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Abstract

A practical computational scheme based on time-dependent density functional theory (TDDFT) and ultrasoft pseudopotential (USPP) is developed to study electron dynamics in real time. A modified Crank-Nicolson time-stepping algorithm is adopted, under planewave basis. The scheme is validated by calculating the optical absorption spectra for sodium dimer and benzene molecule. As an application of this USPP-TDDFT formalism, we compute the time evolution of a test electron packet at the Fermi energy of the left metallic lead crossing a benzene-(1,4)-dithiolate junction. A transmission probability of 5-7%, corresponding to a conductance of 4.0-5.6muS, is obtained. These results are consistent with complex band structure estimates, and Green's function calculation results at small bias voltages.

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Xiaofeng Qian, Ju Li, Xi Lin, Sidney Yip. 2005-10-24. Time-Dependent Density Functional Theory with Ultrasoft Pseudopotential: Real-Time Electron Propagation across Molecular Junction. https://doi.org/10.1103/physrevb.73.035408

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