Metal/oxide Heterointerfaces are important componets in numerous industrial applications, such as composites, coatings, and microelectroncics. The interfacial properties often govern overall performance and reliability of the systems [1]. In order to consider the charge density redistribution at interfaces assuming no a priori type of bonding, first-principles calculations are valid. Most of previous first-principles calculations use specific coherent interface models without lattice misfits, although real metal/oxide interfaces contain lattice misfits. Recently, several first-principles calculations which use the smallest periodic models representing the mismatched interfaces show that the atomic configuration and the bonding nature at interfaces strongly depend on lattice misfits [2,3].
In this study, we investigate M/MgO{222} oxygen-terminated interfaces (M=Ag, Ni), based on the density functional theory. We consider the Ag/MgO interface as the coherent interface because of small lattice misfit, while the Ni/MgO interface with the ratio of the lattice constants, aMgO/aNi ~ 6/5 is treated by the coincidence slab, in which the Ni layer contains 6 × 6 atoms and the Mg and O layers contains 5 × 5 atoms. We evaluate effects of misfit on the adhesion energy, and also discuss the relaxed atomic configuration near the interfaces and the interfacial bonding nature.
[1] F. Ernst, Mater. Sci. Eng., R. 14, 97 (1995).
[2] R. Benedek at al., Phys. Rev. Lett. 84, 3362 (2000).
[3] K. Matsunaga at al., Phys. Rev. B 70, 245427 (2004).
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