Suppression of the spiral-growth mechanism in epitaxial YBa2Cu3O7−x films grown on miscut substrates

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Abstract
The growth mechanism and surface microstructures of epitaxial YBa2Cu3O7−x films are extremely sensitive to substrate miscut angle. The screw dislocation‐mediated growth that is so prominent in YBa2Cu3O7−x films grown on well‐aligned (001) substrates can be completely eliminated by growing YBa2Cu3O7−x on a substrate that is miscut only 2°–3° away from (001). Films grown on miscut near‐(001) LaAlO3 and SrTiO3 substrates consist of overlapping tilted platelets, one c‐axis unit cell thick, that are epitaxially aligned with the underlying crystal lattice. This morphology, and the absence of screw‐growth features, persists even in relatively thick (∼200 nm) films. The dominance of miscut‐aligned growth is explained by the large number of surface steps that act as both nucleation and rapid‐growth sites on a miscut surface.