A Designing Strategy for Fano Resonances in Molecular Junctions

In single-molecule junctions, Fano resonance allows forefficientelectron transport modulation between constructive and destructiveinterferences over a small energy range and can be exploited to increasethe thermoelectricity and the sensitivity of single-molecule sensors.To explore the designing principles for Fano resonances, we have investigatedthe electronic transport properties of alkene- and naphthalene-basedmolecular junctions with molecular conductance orbitals (MCOs). AFano resonance arises from the destructive quantum interference dueto a pair of MCOs with opposite phases and comparable energies, forwhich one is more localized than the other. We introduce an asymmetryfactor to distinguish the Fano resonances from other destructive quantumfeatures. To increase the asymmetry factor, pendant groups coupledat the atomic site where the corresponding MCO has a zero coefficientcan be employed to induce and modulate antiresonances.