Study of YBCO/Au surface using low-temperature scanning tunneling microscopy/scanning tunneling spectroscopy

• Published in: Japanese Journal of Applied Physics Vol. 31; no. 11; pp. 3525 - 3528
• Main Authors: KOYANAGI, M, KASHIWAYA, S, AKOH, H, KOHJIRO, S, MATSUDA, M, HIRAYAùA, F, KAJIMURA, K
• Format: Journal Article
• Language: English
• Published: Tokyo Japanese journal of applied physics 01-11-1992
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Physics; Proximity effects, weak links, tunneling phenomena, and josephson effects, adreev effect, sn and sns junctions; Superconductivity; Gold; Electrical conductivity; Transition metal Compounds; Solid solid interface; Tunnel effect; Surface electron state; Proximity effect; Transition metal; Experimental study; Inorganic compound; Scanning tunneling microscopy; Energy gap; Josephson effect; Barium Copper Yttrium Oxides Mixed; High temperature superconductor
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/jjap.31.3525

A low-temperature scanning tunneling microscope (LTSTM) has been used to study the surface electronic state of a 30-nm-thick Au film deposited on (103)-oriented YBCO thin film. Conductance spectra with the BCS-like dip induced by the superconductivity proximity effect were observed in a small area. Also, spectra with zero-bias conductance peaks were observed in another limited area. Most parts of the areas studied showed constant conductance spectra. Since this fact suggests the existence of a degraded layer on most surfaces of the YBCO film, the Josephson coupling in YBCO/Au/Nb is assumed to occur primarily in this degraded layer.