Benchmark density functional theory calculations for nanoscale conductance

Abstract

We present a set of benchmark calculations for the Kohn-Sham elastic transmission function of five representative single-molecule junctions. The transmission functions are calculated using two different density functional theory (DFT) methods, namely an ultrasoft pseudopotential plane wave code in combination with maximally localized Wannier functions, and the norm-conserving pseudopotential code Siesta which applies an atomic orbital basis set. For all systems we find that the Siesta transmission functions converge toward the plane-wave result as the Siesta basis is enlarged. Overall, we find that an atomic basis with double-zeta and polarization is sufficient (and in some cases even necessary) to ensure quantitative agreement with the plane-wave calculation. We observe a systematic down shift of the Siesta transmission functions relative to the plane-wave results. The effect diminishes as the atomic orbital basis is enlarged, however, the convergence can be rather slow.

Conductance of a conjugated molecule with carbon nanotube contacts

“…Gold metal contacts to molecules has been studied the longest and given the most attention both experimentally and theoretically [2,3,4,5]. The agreement between the experimentally measured currents and the theoretically predicted currents in these systems was difficult to obtain due to the strong dependence of the conductance on the contact geometry [5,6,7,8,9,10]. The correspondence has greatly improved with the introduction of amine linkers [11,12,13].…”

“…To calculate the room temperature conductance, we take the derivative of the current equation with respect to voltage, G = 2e h dET (E)(− ∂f ∂E ), where f is the Fermi-Dirac factor and T is the transmission probabality. The relaxation and transmission calculations are both performed using a double numeric orbital basis to avoid any discrepancies that may arise using a single numeric basis [9]. Additional details on our approach can be found in Ref.…”

Conductance of Sidewall-Functionalized Carbon Nanotubes: Universal Dependence on Adsorption Sites

“…We have done this using the nonequilibrium Green's function (NEGF) formalism [10] as described in Refs. [11,12].…”

Transport properties and electrical device characteristics with the TiMeS computational platform: Application in silicon nanowires

“…This behavior is similar to conductance estimations in transport across molecular junctions where convergence needs to be ensured by enlarging the size of the basis set. 30,31 1. Electrical characteristics Applying our electronic transmission methodology, in this section, the electrical characteristics of SiNW based p-n-p and p-i-p junctions will be explored.…”

“…30 Using a Wannier transformation on DFT Hamiltonians in the PW basis sets enabled them to calculate the transmission function and to compare with a NAOs transport implementation. They concluded that a double zeta polarized basis sets suffices for the particular systems.…”