Electron transport through ribbonlike molecular wires calculated using density-functional theory and Green’s function formalism

Abstract

We study the length dependence of electron transport through three families of rigid, ribbonlike molecular wires. These series of molecules, known as polyacene dithiolates, polyphenanthrene dithiolates, and polyfluorene dithiolates, represent the ultimate graphene nanoribbons. We find that acenes are the most attractive candidates for low-resistance molecular-scale wires because the low-bias conductance of the fluorene-and phenanthrene-based families is shown to decrease exponentially with length, with inverse decay lengths of ␤ = 0.29 Å −1 and ␤ = 0.37 Å −1 , respectively. In contrast, the conductance of the acene-based series is found to oscillate with length due to quantum interference. The period of oscillation is determined by the Fermi wave vector of an infinite acene chain and is approximately 10 Å. Details of the oscillations are sensitive to the position of thiol end groups and in the case of "para" end groups, the conductance is found initially to increase with length.

Molecular conductance in relation to inverse transport theory and to chemical bond order

“…In the present context, we emphasize the results of Visontai et al [9] presented in their Figure 3. This shows the calculated values of the length dependence of the room temperature conductance, for the families (i) to (iii) cited above.…”

“…As this article was nearing completion, an important theoretical article by Visontai et al [9] has appeared. It is the purpose of this penultimate section to summarize the main findings of these authors.…”

“…They show in their Figure 10 that their model is able to reflect the main features of the conductance curves in the longer members of the acene series. Visontai et al [9] conjecture that acenes are attractive as candidates for low-resistance wires in molecular-scale electronic circuits.…”

“…The aim of the theoretical studies of Visontai et al [9] is to examine the electrical conductance of the above molecules, attached via thiol anchor groups to Au electrodes.…”

Spin-dependent electronic conduction along zigzag graphene nanoribbons bearing adsorbed Ni and Fe nanostructures

“…Also, SMEAGOL's extensively parallel architecture facilitates large-scale simulation of electronically complex atomic and molecular systems. Systems to which it has been applied include parallel-plate capacitors, gold nanowires, molecular spin valves, Ni point contacts, H 2 molecules between platinum electrodes and carbon-based nanostructures [16,[25][26][27][28][29][30][31][32][33][34][35][36][37].…”