Building a better unit cell: application to the Ag(111)/GaAs(110) system

First-principles computational techniques are often employed in studies of heterogeneous material interfaces. In many cases the interface to be studied is not coherent or is only coherent over a small length scale and approximations to the unit cell are necessary to carry out the calculations. Instead of using large, computationally intractable unit cells, artificial strain is frequently induced into one or both of the materials making up the interface. This paper presents calculated adhesion energies for a variety of unit cells all chosen to model the Ag(111)/GaAs(110) interface. The results show that the calculated adhesion energy of a single monolayer of Ag is more dependent on the type of artificial strain introduced into the system than it is on the absolute magnitude of strain, and that the surface density of Ag within the monolayer is a crucial factor. The optimized surface structures are also analysed