85 research outputs found
Electronic Phase Diagram of High-T_c Cuprate Superconductors from a Mapping of the In-Plane Resistivity Curvature
We propose that Resistivity Curvature Mapping (RCM) based on the in-plane
resistivity data is a useful way to objectively draw an electronic phase
diagrams of high-T_c cuprates, where various crossovers are important. In
particular, the pseudogap crossover line can be conveniently determined by RCM.
We show experimental phase diagrams obtained by RCM for
Bi_{2}Sr_{2-z}La_{z}CuO_{6+\delta}, La_{2-x}Sr_{x}CuO_{4}, and
YBa_{2}Cu_{3}O_{y}, and demonstrate the universal nature of the pseudogap
crossover. Intriguingly, the electronic crossover near optimum doping depicted
by RCM appears to occur rather abruptly, suggesting that the quantum critical
regime, if exists, must be very narrow.Comment: 4 pages, 3 color figures, final version accepted for publication in
Phys. Rev. Let
Doping evolution of the electronic specific heat coefficient in slightly-doped La2-xSrxCuO4 single crystals
Detailed doping dependence of the electronic specific heat coefficient gamma
is studied for La2-xSrxCuO4 (LSCO) single crystals in the slightly-doped
regime. We find that gamma systematically increases with doping, and
furthermore, even for the samples in the antiferromagnetic (AF) regime, gamma
already acquires finite value and grows with x. This suggests that finite
electronic density of states (DOS) is created in the AF regime where the
transport shows strong localization at low temperatures, and this means the
system is not a real insulator with a clear gap even though it still keeps long
range AF order.Comment: 4 pages, 4 figures, accepted for publication in Journal of Physics:
Conference Series (LT25 proceeding
Magic Doping Fractions in High-Temperature Superconductors
We report hole-doping dependence of the in-plane resistivity \rho_{ab} in a
cuprate superconductor La_{2-x}Sr_{x}CuO_{4}, carefully examined using a series
of high-quality single crystals. Our detailed measurements find a tendency
towards charge ordering at particular rational hole doping fractions of 1/16,
3/32, 1/8, and 3/16. This observation appears to suggest a specific form of
charge order and is most consistent with the recent theoretical prediction of
the checkerboard-type ordering of the Cooper pairs at rational doping fractions
x = (2m+1)/2^n, with integers m and n.Comment: 5 pages, 3 figure, resubmitted to Phys. Rev. Lett. The Tc vs. x
diagram has been added and the discussions have been modified to focus more
on the experimental result
Evolution of the Hall Coefficient and the Peculiar Electronic Structure of the Cuprate Superconductors
Although the Hall coefficient R_H is an informative transport property of
metals and semiconductors, its meaning in the cuprate superconductors has been
ambiguous because of its unusual characteristics. Here we show that a
systematic study of R_H in La_{2-x}Sr_{x}CuO_{4} single crystals over a wide
doping range establishes a qualitative understanding of its peculiar evolution,
which turns out to reflect a two-component nature of the electronic structure
caused by an unusual development of the Fermi surface recently uncovered by
photoemission experiments.Comment: 4 pages, 5 figures, final version appeared in Phys. Rev. Let
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