Atomic Resolution and Nanostructure of YBa 2 Cu 3 O 7-δ Laser-Ablated Thin Films Studied by Scanning Tunnelling Microscopy (STM)

Scanning tunnelling microscopy (STM) is applied to investigate the surface structure of high-quality c -axis oriented laser-ablated thin YBa 2 Cu 3 O 7-δ -films. The main features of the surface are steps of one-unit cell height documenting the two-dimensional growth process of the epitaxial film. For the first time atomic resolution with STM is achieved, indicating a 3.8 Å square lattice on YBa 2 Cu 3 O 7-δ laser-ablated films, as expected from diffraction techniques. Screw dislocations and holes of different sizes are the most frequently observed types of lattice defects in these films.