Orientation of organic molecules in a monolayer vis-à-vis their molecular orbitals and transport gap

Abstract

We form a monolayer of magnetic organic molecules with its plane parallel or perpendicular to the substrate. The molecules in a monolayer are oriented with an external magnetic field followed by immobilization though an electrostatic binding. In this work, from scanning tunneling microscopy (STM) measurements, we show that conductivity, molecular orbitals, and transport gap of the molecules in a monolayer depend on its orientation. From measurements carried out with different tip-to-molecule distances, we observe that the STM tip also influences molecular orbitals and transport-gap of molecules.