Intrinsic Doping at YBCO-metal Interfaces: Quantitative Results

TL;DR

This paper investigates how YBCO-metal interfaces cause intrinsic doping in high-Tc superconductors, revealing a typical charge transfer of 0.13 electrons per copper site, which impacts the optimization of superconducting wires and tapes.

Contribution

It provides quantitative analysis of charge transfer at YBCO-metal interfaces, enhancing understanding of interface-induced doping effects in high-Tc superconductors.

Findings

Charge transfer of 0.13 electrons per Cu site at interfaces.

Band-bending and screening effects explain charge redistribution.

Implications for optimizing high-Tc superconductor devices.

Abstract

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.