Electronic transmission through a polyacene ladder with a substitutional edge impurity

Abstract

We provide an analytical and numerical study of the electronic and transport properties of a ladder system composed of two coupled chains, arranged in the ladder polymer and in the polyacene lattice topology, with a single substitutional edge impurity embedded in one of them. We evidence in particular the connection between local density of states, transmittivity, and occurrence of Fano resonances in the transmission spectra. Comparison of the local density of states and charge transmittivity through the two different ladder systems, as the impurity position is varied, contributes to evidence the nature of resonant interactions occurring for electronic energies coinciding with the impurity energy

Riccati equation for simulation of leads in quantum transport

“…II to the simple case of a lead composed of two coupled semi-infinite periodic chains with a single orbital per each site of energy E 0 , interchain hopping t ⊥ , and intrachain hopping t. The present Appendix recovers the analytic expression for the surface Green's function known in the literature [30,31] for the same system and indicates the simple procedure to follow numerically in the case of any number of chains in the lead. For this problem we have (see Fig.…”

Absolutely continuous energy bands in the electronic spectrum of quasiperiodic ladder networks

“…We specifically work with the Fibonacci quasiperiodic order, though the observation is by no means, restricted to them. Ladder networks within the framework of tight binding model have already been exploited to gain insight into charge transport in DNA [31], to unravel interesting physics related to polymer structures and ployacene lattice topology [32,33]. Comparatively speaking, controlled generation of absolutely continuous portions in the energy spectrum of the ladder networks, disordered or quasi-periodic, still remains to be explored.…”