Orientational dependence of current through molecular films

Abstract

We study the current through molecular films as a function of orientation of the molecules in the film with respect to electrodes. It may change by more than an order of magnitude, depending on the angle between the axis of the molecules and the normal to the electrode. This is a consequence of a strong directional character of $p$-orbitals that determines the conductance through the molecules. We demonstrate this result on an exactly solvable model, and present the calculations for two different experimentally accessible molecular films sandwiched between gold electrodes.