abstract
We present a complete analysis of the temperature dependence of the Hall coefficient R(H)(T) as a function of cerium doping, x, on improved thin films of Pr(2-x)Ce(x)CuO(4 +/-delta) made by pulsed-laser deposition. By mapping its first temperature derivative dR(H)(T)/dT in a temperature-doping phase diagram, we show that some of the most important variations of R(H)(T,x) occur in a T-x range just above the antiferromagnetic (AF) transition, T(N)(x). This area of large dR(H)(T)/dT in the phase diagram collapses at underdoping, very close to the onset of superconductivity at x=0.12. Assuming that this zone remains above T(N)(x), it suggests the presence of a zero-temperature critical point at underdoping in the phase diagram of the electron-doped cuprates on top of the one reported at x(*)similar to 0.165. Both of these critical points can be related to specific transitions in Fermi-surface morphology with doping observed by ARPES. Hence, we conclude that the phase diagram of the n-type family presents two zero-temperature critical points similar to the p-type cuprates, setting clear limiting boundaries for theoretical models, in particular, the absence of long-range AF order between x=0.12 and x(*)similar to 0.165.
keywords
THIN-FILMS; TRANSPORT-PROPERTIES; DOPING DEPENDENCE; CRITICAL-POINT; FERMI-SURFACE; SUPERCONDUCTORS; PR2-XCEXCUO4; BEHAVIOR; METAL
subject category
Physics
authors
Charpentier, S; Roberge, G; Godin-Proulx, S; Bechamp-Laganiere, X; Truong, KD; Fournier, P; Rauwel, P
Groups
acknowledgements
We thank A.-M. Tremblay, C. Bourbonnais, M. Poirier, S. Jandl, P. Richard, R. L. Greene, M. P. Singh, and L. Taillefer for discussions, S. Pelletier for his technical assistance, and J. Beerens for the thickness measurements. We acknowledge the support of the Canadian Institute for Advanced Research and funding from NSERC, FQRNT, and CFI. One of us (P.R.) acknowledges the financial support of CICECO.