Comparison of tunneling through molecules with Mott-Hubbard and with dimerization gaps

TL;DR

This study compares electron tunneling through 1D molecules with Mott-Hubbard and dimerization gaps, revealing that interaction-driven gaps allow larger persistent currents and slower decay with size, impacting molecular electronics.

Contribution

It provides a numerical comparison showing that Mott-Hubbard gaps lead to higher persistent currents than dimerization gaps in 1D molecules.

Findings

Mott-Hubbard gap results in larger persistent current than dimerization gap.

Tunneling current decreases exponentially with molecule size in both cases.

Decay of current is slower in the interacting Mott-Hubbard case.

Abstract

In order to study the tunneling of electrons through an interacting, 1D, dimerized molecule connected to leads, we consider the persistent current in a ring embedding this molecule. We find numerically that, for spinless fermions, a molecule with a gap mostly due to interactions, i.e. a Mott-Hubbard gap, gives rise to a larger persistent current than a molecule with the same gap, but due only to the dimerization. In both cases, the tunneling current decreases exponentially with the size of the molecule, but more slowly in the interacting case. Implications for molecular electronic are briefly discussed.