Computational study of the staircase molecular conductivity of polyoxovanadates adsorbed on Au(111)

Abstract

This computational study presents the molecular conduction properties of two members of the polyoxovanadate (POV) class of molecules, V₆O₁₉ (Lindqvist-type) and V₁₈O₄₂, which have been targeted as possible successors of the materials that are currently used in complementary metal–oxide semiconductor (CMOS) technology. Molecular conductivity calculations on the Lindqvist-type POV absorbed on Au(111) shows a staircase conductivity as function of the applied bias voltage, which is directly related to the oxidation state of the absorbed molecule. After these proof-of-principle calculations we applied the same technique to the larger V₁₈O₄₂, a system featuring many more easily attainable redox states, and hence, in principle even more interesting from the multiple-state resistive (memristive) viewpoint. The calculated transmission strongly suggests that this molecule does not possess staircase conductivity, a fact ascribed to the large number of unpaired electrons in the resting state.