Quantum Transport Through Multiterminal Phenalenyl Molecular Bridges

Abstract

The quantum transport properties of multiterminal molecular bridge systems are theoretically studied with the Green's functions method based on an empirical tight-binding model. As an illustrated example, we adopt a phenalenyl molecule which has a nonbonding singly occupied molecular orbital (SOMO). For a comparative study, first the two-terminal molecular bridges, then the three- and four-terminal molecular bridges are calculated. For the two-terminal case, we find that the transmission spectra significantly depend on the terminal sites connected to the leads. For example, the transmission spectrum has a peak at E=0.0 (SOMO level) as long as both the source and drain are connected to the α sites, but otherwise a dip structure appears at this energy. As a general trend, even when the third and fourth terminals are connected, the transmission spectra do not change considerably from the corresponding spectra of the two-terminal cases. However, some attractive aspects, such as the disappearance of the dip at the SOMO level and a shift in the location of the large loop current, are newly found.