Two critical points have been revealed in the normal-state phase diagram of the electron-doped cuprate superconductor Nd2−xCexCuO4 by exploring the Fermi surface properties of high quality single crystals by high-field magnetotransport. First, the quantitative analysis of the Shubnikov-de Haas effect shows that the weak superlattice potential responsible for the Fermi surface reconstruction in the overdoped regime extrapolates to zero at the doping level xc=0.175 corresponding to the onset of superconductivity. Second, the high-field Hall coefficient exhibits a sharp drop right below optimal doping xopt=0.145 where the superconducting transition temperature is maximum. This drop is most likely caused by the onset of long-range antiferromagnetic ordering. Thus, the superconducting dome appears to be pinned by two critical points to the normal state phase diagram.
@article{arxiv.1403.7398,
title = {Correlation between Fermi surface transformations and superconductivity in the electron-doped high-$T_c$ superconductor Nd$_{2-x}$Ce$_x$CuO$_4$},
author = {T. Helm and M. V. Kartsovnik and C. Proust and B. Vignolle and C. Putzke and E. Kampert and I. Sheikin and E. -S. Choi and J. S. Brooks and N. Bittner and W. Biberacher and A. Erb and J. Wosnitza and R. Gross},
journal= {arXiv preprint arXiv:1403.7398},
year = {2015}
}