Annual Report 2012 - Latvijas Universitātes Cietvielu fizikas institūts

experimental data. We focused on the defect energetics. It is confirmed that an oxygen
vacancy has the lowest formation energy among all single vacancies probed. It is also
established that oxygen Frenkel defects, full Schottky disorder and partial Schottky
disorder accompanied by the growth of a new phase (e.g. a binary oxide) all have
relatively low formation energies and are favorable. The obtained cation exchange
energies are very low on both the A- and B- sublattices of the perovskite structure,
which carries implications as to the stability of the materials and ultimately to the
efficiency of energy conversion
Fig. 1 Co-O-Co oxygen hollow (left) and split (right) interstitial configurations, their
atomic charges, and inter-atomic distances.
3.5
3.0
2.5
2.0
E, eV
1.5
1.0
0.5
, , ,
, cubic phase
hexagonal phase (2H)
0.0
single O vacancy formation energy, eV
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0 0.2 0.4 0.6 0.8 1.0
Fig.2 The cubic (left top) and the hexagonal (2H) (left bottom) BSCF structures are
presented. Right- the total energy and the single vacancy formation energy of the cubic
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