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A First Principles Density Functional Study of Au Deposition on TiN (001) Surface

Abstract: The structure and local electron properties of Au atoms deposited on the TiN (001) surface has been theoretically analyzed using a periodic slab model and density func-tional based calculations. The surface is described by means of a 2x2 cell five layers thick, on which gold atoms are added. Deposition of single atoms on the surface, (θ = 0.25 ML), shows that the preferred site is on-top of Ti atoms, with a metal-surface distance of 2.49 A. The computed adsorption energy for this site is -1.92 eV, only slightly lower than that lying between two Ti surface atoms (-1.90 eV). The on-top nitrogen sites are less favorable by about 0.4 eV. The calculations were carried out using the Perdew-Wang 91 exchange corre-lation functional and ultra soft pseudopotentials, with electronic states represented by a plane-wave expansion. Keywords: Titanium nitride, surface relaxation, Au adsorption, periodic DFT, supercell model. Introduction Transition-metal carbides and nitrides, commonly referred to as refractory hard metals, possess an unusual combination of physical and chemical properties[1] which make them attractive from both a fundamental and technological point of view. They have high melting points and extreme hardness, properties which are typical of covalent crystals, as well as metallic conductivities comparable to those of pure transition metals. These materials have good corrosion resistance and some of them have shown high superconducting transition temperatures.[2] Also they have attracted considerable interest as potential catalysts.[3]