Revealing molecular orbital gating by transition-voltage spectroscopy - Condensed Matter > Mesoscale and Nanoscale Physics

Abstract: Recently, Song et al Nature 462, 1039 2009 employed transition-voltagespectroscopy to demonstrate that the energy $\varepsilon H$ of the highestoccupied molecular orbital HOMO of single-molecule transistors can becontrolled by a gate potential $V G$. To demonstrate the linear dependence$\varepsilon H-V G$, the experimental data have been interpreted by modelingthe molecule as an energy barrier spanning the spatial source-drain region ofmolecular junctions. Since, as shown in this work, that crude model cannotquantitatively describe the measured $I$-$V$-characteristics, it is importantto get further support for the linear dependence of $\varepsilon H$ on $V G$.The results presented here, which have been obtained within a model of apoint-like molecule, confirm this linear dependence. Because the two modelsrely upon complementary descriptions, the present results indicate that theinterpretation of the experimental results as evidence for a gate controlledHOMO is sufficiently general.

Author: Ioan Baldea

Source: https://arxiv.org/