[Zurück]

B. Stöger, M. Hieckel, F. Mittendorfer, Z. Wang, M. Schmid, G. Parkinson, D. Fobes, J. Peng, J. Ortmann, A. Limbeck, Z. Mao, J. Redinger, U. Diebold:
"Point defects at cleaved Sr_n+1Ru_nO_3n+1(001) surfaces";
Physical Review B, 90 (2014), S. 1654381 - 1654386.

The (001) surfaces of cleaved Sr3 Ru2 O7 and Sr2 RuO4 samples were investigated using low-temperature scanning tunneling microscopy and density functional theory calculations. Intrinsic defects are not created during cleaving. This experimental observation is consistent with calculations, where the formation energy for a Sr and O vacancy, 4.19 eV and 3.81 eV, respectively, is significantly larger than that required to cleave the crystal, 1.11 eV/(1 × 1) unit cell. Surface oxygen vacancies can be created through electron bombardment, however, and their appearance is shown to vary strongly with the imaging conditions. Point defects observed on as-cleaved surfaces result from bulk impurities and adsorption from the residual gas.