Where are holes in Y_{1-x}Pr_xBa2Cu3O7 ?

TL;DR

This paper investigates how Pr doping affects oxygen hole character in Y_{1-x}Pr_xBa2Cu3O7, providing insights into the mechanisms behind superconductivity suppression and distinguishing between competing theoretical models.

Contribution

It introduces a method to determine the ratio of planar to axial oxygen hole character, helping to differentiate between models predicting hole transfer effects.

Findings

Pr doping causes a transition from $p_{\sigma}$ to $p_{\pi}$ holes.

The study offers a way to measure the planar versus axial hole ratio.

Results support models predicting oxygen hole transfer upon Pr doping.

Abstract

Recent experiments by Mertz et al (Phys. Rev. B55, 9160, 1997) demonstrated that the loss of superconductivity upon Pr doping is associated with the change of the character of the oxygen holes from $p_{\sigma}$ to $p_{\pi}.$ This experiment sheds new light onto the long-standing problem of $T_{c}$ suppression by Pr, and helps to rule out a number of theoretical models, leaving only those which predict such a transfer of the O holes. To distinguish between the two models that do predict such an effect, one has to access the ratio of the planar and axial character of the holes in both models. We do so in this paper.