Correlation between Fermi surface transformations and superconductivity in the electron-doped high-$T_c$ superconductor Nd$_{2-x}$Ce$_x$CuO$_4$

摘要

Two critical points have been revealed in the normal-state phase diagram ofthe electron-doped cuprate superconductor Nd$_{2-x}$Ce$_x$CuO$_4$ by exploringthe Fermi surface properties of high quality single crystals by high-fieldmagnetotransport. First, the quantitative analysis of the Shubnikov-de Haaseffect shows that the weak superlattice potential responsible for the Fermisurface reconstruction in the overdoped regime extrapolates to zero at thedoping level $x_c = 0.175$ corresponding to the onset of superconductivity.Second, the high-field Hall coefficient exhibits a sharp drop right belowoptimal doping $x_{\mathrm{opt}} = 0.145$ where the superconducting transitiontemperature is maximum. This drop is most likely caused by the onset oflong-range antiferromagnetic ordering. Thus, the superconducting dome appearsto be pinned by two critical points to the normal state phase diagram.