Charge redistribution at YBa_2Cu_3O_7-metal interfaces

摘要

Charge redistribution at interfaces is crucial for electronic applications of high-T_c superconductors, since the band structure is modified on a local scale. The authors address the normal-state electronic structure of YBa_2Cu_3O_7 (YBCO) at an YBCO-metal contact by first principles calculations for prototypical interface configurations. They derive quantitative results for the intrinsic doping of the superconducting CuO_2 planes due to the metal contact. Their findings can be explained in terms of a band-bending mechanism, complemented by local screening effects. The authors determine a net charge transfer of 0.09-0.13 electrons in favor of the intraplane Cu sites, depending on the interface orientation.