Planar tunnel junction studies of quasiparticle bound states in vortices in ultrathin films

✍ Scribed by Shih-ping Hsu; J.A. Chervenak; J.M. Valles Jr

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 587 KB
• Volume: 2
• Category: Article
• ISSN: 0964-1807
• DOI: 10.1016/0964-1807(94)90071-x

✦ Synopsis

The application of a magnetic field perpendicular to the plane of a type-II superconducting film leads to the formation of vortices in it. We have made a series of tunneling measurements on quench condensed ultrathin films to investigate the influence of film structure on how the tunneling density of states is affected by magnetic field. We find that films with microscopically homogeneous structure show clear evidence of quasiparticle states bound to vortices. In contrast, granular films with high normal state sheet resistances exhibit no bound states associated with the vortices. However, by reducing the sheet resistance of the granular films and thereby enhancing the intergrain coupling, bound states appear.