Revised tight-binding second moment potential for transition metal surfaces

Abstract

Usual semi-empirical atomic interactions, like second moment approximation potential with parameters fitting bulk properties are known to underestimate the absolute values of surface energies. In the same way, it is also difficult to reproduce their variation from an element to the other which is however very important for further studying surface alloying phenomena or complex nanoalloys. As it is indeed impossible to fit simultaneously both cohesive energies and surface energies with this type of potential, an alternative proposed here is to accept a single global lowering of all the surface energies introduced as an additional constraint in determining some revised SMA parameters. Using a ratio of 0.5 between calculated and experimental values of surface energies allows recovering satisfactory variations from an element to the others extending the possibility of studying a larger set of surface alloy systems, with two or more components.