Piskunov, Sergej; Heifets, Eugene; Jacob, Timo; Kotomin, Eugene A.; Ellis, Donald E.; Spohr, Eckhard:

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

In: Physical Review / B, Condensed matter and materials physics, Jg. 78 (2008) ; Nr. 12, S. 121406(R)
ISSN: 1098-0121, 0163-1829, 0556-2805
Zeitschriftenaufsatz / Fach: Chemie
Fakultät für Chemie
Abstract:
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 ( ˜0.5eV 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.