Gate-Tunable Fano Resonances in Parallel-Polyacene-Bridged Carbon Nanotubes

A nanoscale device functioning in electronic transport via electrically tunable Fano resonances has huge potential for applications but is still rarely available to date. Using first-principles calculations, we show that a double-path molecular junction under an applied gate voltage can realize such a goal. It turns out that the crosstalk between two paths can be mapped to an ideal Fano-Anderson model, a single-path junction coupling to an isolated quantum dot. Its line shape of Fano resonance progressively evolves from an asymmetric to a symmetric Breit-Wigner peak when the gate voltage increases moderately. The significance of this system is illustrated by the sizable coupling strength that scales linearly with the gate voltage. On the basis of this scheme, we propose that these tunable Fano molecular junctions can serve as efficient transistors and thermoelectric energy conversion devices.