Scaling Properties and Related Issues in the Charge Transport through Molecular Junctions

Abstract

In this paper, we discuss a law of corresponding states (LCS) deduced theoretically and validated experimentally against a variety of current-voltage I-V data measured in molecular junctions fabricated under different experimental platforms. It holds, e.g.: for benchmark nanojunctions based on molecules with σ-saturated aliphatic backbones and localized electrons, and molecules containing π-conjugated rings and delocalized electrons, wherein conductance varies over five orders of magnitude; for CP-AFM (conducting probe atomic force microscope) and STM (scanning tunneling microscope) break junctions; for molecular junctions having typical metallic (silver, gold, platinum) or graphene electrodes. Unprecedented, this law of corresponding states is able to quantitatively reproduce measurements on real junctions very accurately without need to empirically adjust any parameter to experiment. This is in contrast even with the celebrated van der Waals law of corresponding states, which, without parameter adjustment to experiment, provides a rather poor quantitative description of real (classical) fluids. This LCS emphasizes the special role played by the peak (alias transition) voltage in molecular electronics.