STUDIES OF LAALO3(100) SURFACES USING RHEED AND REM .2. 5X5 SURFACE RECONSTRUCTION

For the first time, 5 X 5 surface reconstruction on annealed LaAlO3{10 0} surfaces is observed with reflection high-energy electron diffracti on (RHEED) and reflection electron microscopy (REM). Most of the {100} surface areas are covered by the reconstructed layer. The presence of twin boundaries and protrusion contaminants on the surface has no inf luence on the formation of the reconstruction. Surface steps may enhan ce the surface reconstruction but are not essential to initiate the re construction. This feature is interpreted based on the adsorption mode ls of oxygen on surface steps.