Integrated Ferroelectrics, 123:26–31, 2011 Copyright © Taylor & Francis Group, LLC ISSN: 1058-4587 print / 1607-8489 online DOI: 10.1080/10584587.2011.570593 First-Principles Calculations of SrZrO 3 (001) Surfaces R. I. EGLITIS ∗ Institute of Solid State Physics, University of Latvia, 8 Kengaraga Str., Riga LV1063, Latvia The results of calculations of surface relaxations, rumplings, and charge distribution for the SrZrO 3 (001) surface using ab initio code CRYSTAL and a hybrid description of exchange and correlation are presented. Both SrO and ZrO 2 terminations of the SrZrO 3 (001) surface are considered. On the (001) surfaces all upper and third layer atoms relax inward, while outward relaxations of all atoms in the second layer are found with the sole exception of SrO-terminated SrZrO 3 (001) surface second layer O atom. Calculated surface rumpling for the SrO-terminated SrZrO 3 (001) surface 6.77% of the lattice constant is by a factor of ten larger than the surface rumpling for the ZrO 2 -terminated SrZrO 3 (001) surface 0.72% of a o . A considerable increase in the Zr-O chemical bond covalency near the SrZrO 3 (001) surface as compared to the bulk is predicted. Keywords Ab initio calculations; surface structure; SrZrO 3 Introduction Strontium zirconate SrZrO 3 is of technological interest because of applications in fuel cells, hydrogen gas sensors and steam electrolysis [1]. For all these SrZrO 3 applications, the surface structure and the related surface electronic and chemical properties are of primary importance. Ab initio calculations of SrZrO 3 surface characteristics are useful to understand processes in which surfaces play a crucial role, such as the chemistry of surface reactions, interface phenomena, and adsorption. Considering high technological importance of SrZrO 3 , it is surprising that during the last years only a small number of theoretical ab initio studies exist dealing with SrZrO 3 (001) surfaces [2–5]. First ab initio studies for the SrZrO 3 (001) surface was performed by Evarestov et al. [2]. Authors used three slab models with different surface terminations to calculate the various surface characteristics including surface energies, atomic charges and density of electronic states [2, 3]. Sambrano et al. [4] investigated the structural and electronic properties of SrZrO 3 selected surfaces by means of density functional theory. They analyzed the relaxation effects for two symmetric and asymmetric SrZrO 3 (001) surface terminations. They discussed the electronic and energy band properties on the basis of band structure as well as density of states calculations [4]. Wang and Arai [5] used density functional calculations to investigate the (001) surface of cubic SrZrO 3 with both SrO and ZrO 2 termination. They found that the SrO surface is similar to its counterpart in Received May 26, 2010; in final form July 1, 2010. ∗ Corresponding author. E-mail: eglitis@yahoo.com 26