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Phys. Rev. B 78, 121406(R) (2008) [4 pages]

Electronic structure and thermodynamic stability of LaMnO3 and La1−xSrxMnO3 (001) surfaces: Ab initio calculations

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Sergei Piskunov1,2,*, Eugene Heifets3, Timo Jacob4, Eugene A. Kotomin2,3, Donald E. Ellis5, and Eckhard Spohr1
1Department of Theoretical Chemistry, University of Duisburg-Essen, Universitätstrasse 2, D-45141 Essen, Germany
2Institute for Solid State Physics, University of Latvia, 8 Kengaraga Street, Riga LV-1063, Latvia
3Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
4Department of Electrochemistry, Ulm University, D-89069 Ulm, Germany
5Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208-3108, USA

Received 13 August 2008; published 24 September 2008

We present the results of ab initio hybrid density-functional calculations of the atomic and the electronic structures of LaMnO3 (LMO) and La1−xbSrxbMnO3 (001) surfaces. The total energies obtained from these calculations were used to analyze thermodynamic stability of the surfaces. We predict Sr and O vacancy segregation to the surface to occur with similar energies (∼0.5 eV per defect). In pure LMO only MnO2 termination is thermodynamically favorable under typical operational conditions of a cathode in solid oxide fuel cells, whereas Sr doping makes La(Sr)O termination favorable. Finally, the role of Sr doping in cathode degradation is discussed.

© 2008 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.78.121406
DOI:
10.1103/PhysRevB.78.121406
PACS:
73.20.At, 71.15.Mb

*sergej.piskunov@uni-due.de

 
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