Roles of the first atomic layers in growth of SrTiO3 films on LaAlO3 substrates

Growth behaviors of SrTiO3/LaAlO3 films could be varied substantially by co ntrolling terminating atomic layers of the substrates. In a film on the LaO -terminated substrate, strain-induced roughening was observed. In a film on the AlO2-terminated substrate, the first atomic layer of the interface see med to have lots of defects. However, the stress became quickly relaxed, so a SrTiO3 film could be grown in a layer-by-layer mode after a few monolaye rs. All these observations could be explained in terms of chemical matching between the atomic layers at the interface. (C) 1999 American Institute of Physics. [S0003-6951(99)01715-5].