Current Nonconservation of Molecular Devices in the Presence of a Nonlocal Potential

L. Q. Lai, J. Chen, Q. H. Liu, Y. B. Yu

Published 2019-02-23Version 1

The electronic transport characteristics are general topics in the studies of mesoscopic systems and molecular devices that have received considerable attentions in view of their future technological importance. The current densities are, however, often found to dissatisfy the continuity condition when nonlocal potentials are included in the Hamiltonian of interest, which is quite relevant in the context of first-principles calculations. In this paper, we discuss the problems of current conservation, and show that they stem from the improper approximations brought in for electron-electron interactions and the inappropriate definition in pseudopotential implementations, respectively. We propose a statistic average formalism as well as a reasonable definition to deal with related issues, and perform numerical simulations of a quasi-one-dimensional electron gas to further demonstrate the results.