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Comparative density-functional LCAO and plane-wave calculations of LaMnO3 surfaces

Evarestov, R. A. and Kotomin, E. A. and Mastrikov, Yu. A. and Gryaznov, D. and Heifets, E. and Maier, J. (2005) Comparative density-functional LCAO and plane-wave calculations of LaMnO3 surfaces. Physical Review B, 72 (21). Art. No. 214411. ISSN 1098-0121. http://resolver.caltech.edu/CaltechAUTHORS:EVAprb05

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Abstract

We compare two approaches to the atomic, electronic, and magnetic structures of LaMnO3 bulk and the (001), (110) surfaces—hybrid B3PW with optimized LCAO basis set (CRYSTAL-2003 code) and GGA-PW91 with plane-wave basis set (VASP 4.6 code). Combining our calculations with those available in the literature, we demonstrate that combination of nonlocal exchange and correlation used in hybrid functionals allows to reproduce the experimental magnetic coupling constants Jab and Jc as well as the optical gap. Surface calculations performed by both methods using slab models show that the antiferromagnetic (AF) and ferromagnetic (FM) (001) surfaces have lower surface energies than the FM (110) surface. Both the (001) and (110) surfaces reveal considerable atomic relaxations, up to the fourth plane from the surface, which reduce the surface energy by about a factor of 2, being typically one order of magnitude larger than the energy difference between different magnetic structures. The calculated (Mulliken and Bader) effective atomic charges and the electron density maps indicate a considerable reduction of the Mn and O atom ionicity on the surface.


Item Type:Article
Additional Information:©2005 The American Physical Society (Received 22 July 2005; revised 22 September 2005; published 8 December 2005) The authors are greatly indebted to F. Illas, H.-U. Habermeier, R. Merkle, J. Fleig, L. Kantorovich, J. Gavartin, G. Khaliullin, A. Boris, and N. Kovaleva for many stimulating discussions. This study was partly supported by the German-Israeli Foundation Grant No. G-703.41.10 (J.M., E.K., and Y.M.) and by the A. von Humboldt Foundation (R.E.).
Subject Keywords:lanthanum compounds; density functional theory; band structure; magnetic structure; surface states; exchange interactions (electron); antiferromagnetic materials; ferromagnetic materials; surface energy
Record Number:CaltechAUTHORS:EVAprb05
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:EVAprb05
Alternative URL:http://dx.doi.org/10.1103/PhysRevB.72.214411
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2027
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:02 Mar 2006
Last Modified:26 Dec 2012 08:47

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