First-Principles Approach to the Conductance of Covalently Bound Molecular Junctions
[1];
[1];
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Foundry; Univ. of California, Berkeley, CA (United States). Dept. of Physics
- Univ. Paris-Saclay, Gif-sur-Yvette (France). Service de Recherches de Métallurgie Physique
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Foundry; Univ. of California, Berkeley, CA (United States). Dept. of Physics; Kavli Energy Nanosciences Inst. at Berkeley, CA (United States)
In this study, we develop a first-principles approach for accurate conductance calculations of covalently bound molecular junctions. Our approach extends the DFT+$$Σ$$ method, an approximate GW-based self-energy correction scheme acting on a tractable molecular subspace (based on a gas-phase reference of the same dimension) that corrects level alignment in the junction relative to density functional theory (DFT). We introduce a new extended gas-phase reference system, consisting of the molecule and several lead atoms, whose frontier orbitals maximally project onto the conducting orbitals of the junction. With this choice of reference, our self-energy correction to the Kohn–Sham Hamiltonian takes into account mixing of the gas-phase reference orbitals upon the formation of the junction. We apply our generalized DFT+$$Σ$$ approach to a series of alkane–chain junctions in which the molecules are covalently bound to the leads via carboxyl terminal groups. Our results lead to conductance values in quantitative agreement with experiment. We also revisit the well-studied Au–bipyridine–Au junction and show that we recover the original DFT+$$Σ$$ approach for relatively weak donor–acceptor molecule–lead binding.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02- 05CH11231
- OSTI ID:
- 1530182
- Journal Information:
- Journal of Physical Chemistry. C, Vol. 123, Issue 11; ISSN 1932-7447
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
The energy level alignment at metal–molecule interfaces using Wannier–Koopmans method
Self-consistent Kohn-Sham method based on the adiabatic-connection fluctuation-dissipation theorem and the exact-exchange kernel