Huckel I-V 3.0: a self-consistent model for molecular transport and its applications

Huckel I-V 3.0 can be a very useful model in explaining many different physical characteristics of molecular conductors that have been experimentally observed. The authors apply this model to investigate the origin of asymmetry in the current-voltage (I-V) characteristics observed in a recent break junction measurement for a symmetric molecule. We achieve good agreement between theoretical and experimental I-V characteristics, both in shape as well as overall magnitude. We conclude that such asymmetry arises due to unequal coupling with the contacts which generates asymmetry in charging. We also study alkanethiol I-V characteristics observed in a recent nanopore experiment. We achieve an excellent match between calculated and experimental results. One of the main features of Huckel I-V 3.0 is that a third terminal (as a gate) can be added to the system with relative ease. In order to showcase this strength of our model we perform three terminal calculations on single molecules. We study both alkanethiol chains and conjugated molecules as a molecular transistor and observe that alkanethiol molecules show better transistor performance.