Interfacial defects in YBa₂Cu₃O_7-δ/SrTiO₃(0 0 1) heterostructures studied by aberration-corrected ultrahigh-resolution electron microscopy

The microstructure of interfacial defects in YBa2Cu3O7-δ/SrTiO3(0 0 1) heterostructures has been investigated by aberration-corrected ultrahigh-resolution electron microscopy. We determine that c-axis-oriented YBa2Cu3O7-δ thin films epitaxially grow on SrTiO3(0 0 1) with two types of interface structure. The coalescence of nucleation sites with different types of interface structure leads to the formation of antiphase domain boundaries in YBa2Cu3O7-δ thin films, which terminate at planar faults with different configurations near the interface. Stand-off misfit dislocations are observed and the dislocation core structure is explored. Based on the interface structure and interfacial defects, the initial growth mode of YBa2Cu3O7-δ thin films on SrTiO3(0 0 1) is discussed.