Electronic Structure of Molecules, Surfaces, and Molecules on Surfaces with the Local Modified Becke–Johnson Exchange–Correlation Potential

The knowledge of
electronic properties of matter is the key to
the understanding of its properties and to propose useful applications.
To model hybrid organic/inorganic systems with the plane-wave approach,
large supercells with many atoms are usually necessary to minimize
artificial interactions between periodic images. For such systems,
accurate approximations to the exchange–correlation functional
of density functional theory, such as hybrid functionals, become computationally
expensive, and cheaper approaches need to be considered. Here, we
apply the local modified Becke–Johnson exchange–correlation
potential to free molecules and surfaces and study its accuracy for
calculated ionization potentials. This quantity being important to
understand the band alignment of composite heterogeneous systems,
we demonstrate the application of the potential to the electronic
structure calculation of an exemplary composite semiconductor/molecule
system, namely, a F6-TCNNQ molecule adsorbed on a hydrogenated Si(111)
surface.