Exchange and correlation in molecular wire conductance: non-locality is the key
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EvansVanVoorhis09b.pdf
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Author(s)
Evans, Jeremy S.
Vydrov, Oleg A.
Van Voorhis, Troy
Date Issued
July 2009
Journal
Journal of Chemical Physics
Publisher
American Institute of Physics
Citation
Evans, Jeremy S., Oleg A. Vydrov, and Troy Van Voorhis. “Exchange and Correlation in Molecular Wire Conductance: Nonlocality Is the Key.” The Journal of Chemical Physics 131.3 (2009): 034106.
Version
Author's final manuscript
Abstract
We study real-time electron dynamics in a molecular junction with a variety of approximations to the electronic structure, toward the ultimate aim of determining what ingredients are crucial for the accurate prediction of charge transport. We begin with real-time, all electron simulations using some common density functionals that differ in how they treat long-range Hartree–Fock exchange. We find that the inclusion or exclusion of nonlocal exchange is the dominant factor determining the transport behavior, with all semilocal contributions having a smaller effect. In order to study nonlocal correlation, we first map our junction onto a simple Pariser–Parr–Pople (PPP) model Hamiltonian. The PPP dynamics are shown to faithfully reproduce the all electron results, and we demonstrate that nonlocal correlation can be readily included in the model space using the generator coordinate method (GCM). Our PPP-GCM simulations suggest that nonlocal correlation has a significant impact on the I-V character that is not captured even qualitatively by any of the common semilocal approximations to exchange and correlation. The implications of our results for transport calculations are discussed.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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Creative Commons Attribution-Noncommercial-Share Alike 3.0
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DOI of Published Version
https://doi.org/10.1063/1.3179754
