Intrinsic doping at YBCO-metal interfaces: Quantitative resultsU. Schwingenschlögl and C. Schuster
Institut für Physik, Universität Augsburg - 86135 Augsburg, Germany
received 15 October 2006; accepted in final form 11 December 2006; published February 2007
published online 30 January 2007
Charge redistribution in high-Tc superconductors due to structural defects or interfaces is known to be crucial for electronic applications as the band structure is modified on a local scale. In order to investigate these effects in more detail, we address the normal-state properties of YBa2Cu3O7 (YBCO) in the vicinity of YBCO-metal interfaces by electronic structure calculations for well relaxed interface configurations. Our findings can be interpreted in terms of a band-bending mechanism complemented by local screening effects. We derive quantitative results for the intrinsic doping of the superconducting CuO2 planes due to the metal interface. In particular, the net charge transfer amounts to 0.13 electrons in favour of each intraplane copper site, which appears to be a typical value for interfaces of high-Tc superconductors, thus opening great possibilities for a systematic optimization of wires and tapes from high-Tc materials.
73.20.At - Surface states, band structure, electron density of states.
73.40.Jn - Metal-to-metal contacts.
74.25.Jb - Electronic structure.
© Europhysics Letters Association 2007