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First‐Principles Calculations for Niobium Atoms on a Sapphire Surface
Author(s) -
Kruse Carsten,
Finnis Michael W.,
Milman Victor Y.,
Payne Michael C.,
Vita Alessandro,
Gillan Michael J
Publication year - 1994
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1994.tb07011.x
Subject(s) - niobium , atomic orbital , density functional theory , atom (system on chip) , atomic physics , sapphire , monolayer , materials science , molecular physics , chemistry , computational chemistry , nanotechnology , physics , electron , laser , optics , quantum mechanics , computer science , metallurgy , embedded system
We report first‐principles, self‐consistent calculations of the equilibrium structure, election density, and total energy of a niobium monolayer on a sapphire (0001) surface. The calculations, which are based on the density functional theory in the local density approximation, use norm‐conserving pseudopotentials and a basis of plane waves. We work with a slab which is three Al–O–Al layers in thickness and we assume that the surface Al atoms are replaced by Nb. All the atomic positions are relaxed to minimize the total energy. In contrast to the clean surface, on which the Al atoms relax inwards almost to the level of the surface oxygen, the Nb atoms relax only slightly inwards from the sites where the next Al atoms would sit if the bulk structure were extended. The Nb atoms are partially ionized and there is strong directional bonding, due to the hybridization of d‐orbitals on Nb with the oxygen p‐orbitals. The work of adhesion is 13 eV per Nb atom.