Fano Resonance in Single‐Molecule Junctions

Abstract

The Fano resonance in single-molecule junctions could be created by interaction with discrete and continuous molecular orbitals and enables effective electron transport modulation between constructive and destructive interference within a small energy range. However, direct observation of Fano resonance remains unexplored because of the disappearance of discrete orbitals by molecule-electrode coupling. We demonstrated the room-temperature observation of Fano resonance from electrochemical gated single-molecule conductance and current-voltage measurements of a para-carbazole anion junction. Theoretical calculations reveal that the negative charge on the nitrogen atom induces a localized HOMO on the molecular center, creating Fano resonance by interfering with the delocalized LUMO on the molecular backbone. Our findings demonstrate that the Fano resonance in electron transport through single-molecule junctions opens pathways for designs of interference-based electronic devices.

Fano resonance in molecular junctions of spin crossover complexes

“…Obviously, the two spin states of M2 trigger notably different signals in conductance under gate voltages, which can be easily captured by experiments. 27 From another point of view, it is interesting that three states of conductance can be detected in MJ2 when both the spin-state transition and the gate voltage are taken into account. The high/low conductance state (named S 1 /S À1 ) is induced by the Fano peak/dip and the intermediate conductance state (S 0 ) by the low-spin state.…”

“…The merit of Fano resonance for molecular devices has been illustrated by recent experiments. [24][25][26][27] Nonetheless, the achievement of Fano resonance using the SCO complex and its application in molecular switches have been hardly explored up to now.…”

“…In this paper, we aim to develop a new molecular switch paradigm that combines the spin crossover complex and the Fano resonance, with the potential to function at room temperature and have better switch performance. 16,27 Two primary questions are thereby raised: (i) the achievement of Fano resonance in molecular junctions of SCO complexes; and (ii) the optimization of switching performance through the modulation of Fano resonance in these junctions. For addressing these questions, density-functional theory (DFT) calculations are employed, with the non-equilibrium Green's function (NEGF) technique.…”