Physisorption of 4-n-octyl-4′-cyanobiphenyl (8CB) molecules on MoS2: interpretation of pairing phenomenum

We have interpreted recent results describing precisely the structure of an organic molecule, the 4-n-octyl-4′-cyanobiphenyl (8CB), physisorbed on an inorganic crystal, the molybdenum disulphide (MoS2). A 1D model corresponding to the observation of quasi-1D structures called lamellae has been used. The observed alternate stacking type of lamella appears as a direct evidence of the connection between the commensurabilities in the two directions. Moreover, we have found a particularly high value for the molecule–substrate potential corrugations, indicating that the dipole moment of 8CB molecules could play a fundamental role in the molecule–substrate interactions.