Probing Quantum Transport by switching Anchor Positions

A novel approach towards probing quantum transport through the molecular junction comprising of benzene molecule terminated by thiol endgroups stringed to two gold electrical contacts was suggested by switching the anchorthiol endgroup positions from meta to para and their corresponding stress and conductance behaviour was computed. Similar molecular junction was formed from anthracene and its charge transport characteristics-Current-Voltage, Conductance-Voltage, Differential conductanceVoltage response were examined at room temperature. The effect of variation of the bond angle on stress and conductance of benzenedithiol (BDT) and anthracenedithiol (ADT) molecules with respect to gold electrodes was anatomized using Extended Huckel Theory (EHT) based semi-empirical model. The simulated results revealed that the para position exhibited higher conduction on account of constructive interference in comparison to meta position whereas latter exhibited higher stress because of destructive interference that led to realignment of π-cloud and hence more stress on the system under observation. This behaviour was demonstrated in both the molecules. The charge transport properties of ADT were elucidated once by considering the endgroup anchor at para position and then at meta position and we concluded that the manipulating these geometric parameters led to quantum interference which affected the overall electron transport and provided us with an insight about the phenomena at nanometre-scale, which could be helpful towards fabricating molecular devices based on these molecules.