For both electron- and hole-doped cuprates, superconductivity appears in the vicinity of suppressed broken symmetry order, suggesting that quantum criticality plays a vital role in the physics of these systems. A confounding factor in identifying the role of quantum criticality in the electron-doped systems is the competing influence of chemical doping and oxygen stoichiometry. Using high quality thin films of Pr2CuO4±δ, we tune superconductivity and uncover the influence of quantum criticality without Ce substitution. We observe magnetic quantum oscillations that are consistent with the presence of small hole-like Fermi surface pockets, and a large mass enhancement near the suppression of superconductivity. Tuning these materials using only oxygen stoichiometry allows the observation of quantum oscillations and provides a new axis with which to explore the physics underlying the electron-doped side of the cuprate phase diagram.
@article{arxiv.1510.04268,
title = {Quantum oscillations suggest hidden quantum phase transition in the cuprate superconductor Pr$_{2}$CuO$_{4\pm\delta}$},
author = {Nicholas P. Breznay and Ross D. McDonald and Yoshiharu Krockenberger and K. A. Modic and Zengwei Zhu and Ian M. Hayes and Nityan L. Nair and Toni Helm and Hiroshi Irie and Hideki Yamamoto and James G. Analytis},
journal= {arXiv preprint arXiv:1510.04268},
year = {2019}
}