The (mostly) insulating behaviour of PrBa2Cu3O7-d is still unexplained and even more interesting since the occasional appearance of superconductivity in this material. Since YBa2Cu3O7-d is nominally iso-structural and always superconducting, we have measured the electron momentum density in these materials. We find that they differ in a striking way, the wavefunction coherence length in PrBa2Cu3O7-d being strongly suppressed. We conclude that Pr on Ba-site substitution disorder is responsible for the metal-insulator transition. Preliminary efforts at growth with a method to prevent disorder yield 90K superconducting PrBa2Cu3O7-d crystallites.
@article{arxiv.cond-mat/9805225,
title = {Hole depletion and localization due to disorder in insulating PrBa2Cu3O7-d: a Compton scattering study},
author = {Abhay Shukla and Bernardo Barbiellini and Andreas Erb and Alfred A. Manuel and Thomas Buslaps and Veijo Honkimaki and Pekka Suortti},
journal= {arXiv preprint arXiv:cond-mat/9805225},
year = {2009}
}
Comments
4 pages, 3 figures, revised version submitted to PRL