PERIODIC STEP STRUCTURE OF CLEAN AND YBA2CU3O7-DELTA-COVERED VICINAL SRTIO3(001) SURFACES

We have studied the structure of a stable vicinal SrTiO3(001) surface by UHV scanning tunneling microscopy. We find that the regular nanosca le step structure on the vicinal surface strongly influences the growt h of c-axis-oriented YBa2Cu3O7-delta (YBCO) thin films. It generates a n almost periodic surface structure of the YBCO films. This substrate- mediated control of the film growth is particularly important, because the resultant YBCO microstructure leads to an in-plane anisotropy of the transport properties in the high-temperature superconducting mater ial.