Surface Topography and Tunneling Spectroscopy in High-Temperature Superconducting Thin Films by Scanning Tunneling Microscopy

R. T. Kao；J. H. Horng；S. J. Wang；J. Y. Juang；K. H. Wu；T. M. Uen；Y. S. Gou；T. H. Yang

Chinese Journal of Physics

34卷2S期（1996 / 04 / 01）

688 - 692

英文

The surface morphology and tunneling spectroscopies of the YBa2Cu3O7-x (YBCO) and TIBa2Ca2Cu3O9+x, (Tl-1223) high-T, superconducting thin films deposited on LaAlO3(100) substrates uere investigated by scanning tunneling microscopy (STM). The preliminary results show that although both systems have a common layer-like surface structure, the grain morphologies are quite different suggesting that they may follow different growth mechanisms probably due to the different preparation methods used. In addition, the tunneling current-voltage characteristics (IVCs) maniiested features akin to that of charging effect-induced single electron tunneling in both systems. As a result, the gap-like structure observed in the dI/dv-v curves may no: be reflecting the superconducting energy gaps as commonly conceived.