Energy gaps and phonon structures in tunneling spectra of Bi2Sr2Ca1Cu2O8+x and Bi2Sr2Ca2Cu3O10+y superconductors

✍ Scribed by R. Koltun; M. Hoffmann; P.C. Splittgerber-Hünnekes; G. Güntherodt; V.V. Moshchalkov; L.I. Leonyuk

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 349 KB
• Volume: 165-166
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/s0921-4526(09)80369-4

✦ Synopsis

Polycrystalline Bi-2212 or Bi-2223 systems and single crystals of the Bi-2212 system were investigated at several temperatures by means of the break-junction and pointcontact tunneling techniques, respectively. The measured averaged gap values are 2Ll=65±4 meV in the Bi-2223 and 2Ll=45±5 meV in the Bi-2212 systems, with 2Ll/k s T c =7.3 and 6.8, respectively. A dc-Josephson-type supercurrent could be observed in polycrystalline Bi-2212 samples in addition to the usual gap structure. The point-contact tunneling s::rectra of Bi-2212 single crystals exhibit structures in the second derivative d 2 I/dV which we interpret as inelastic tunneling processes due to electron-phonon scattering in the barrier region.