Recent studies of the high-Tc superconductor La_(1.6-x)Nd_(0.4)Sr_(x)CuO_(4) (Nd-LSCO) have found a linear-T in-plane resistivity rho_(ab) and a logarithmic temperature dependence of the thermopower S / T at a hole doping p = 0.24, and a Fermi-surface reconstruction just below p = 0.24 [1, 2]. These are typical signatures of a quantum critical point (QCP). Here we report data on the c-axis resistivity rho_(c)(T) of Nd-LSCO measured as a function of temperature near this QCP, in a magnetic field large enough to entirely suppress superconductivity. Like rho_(ab), rho_(c) shows an upturn at low temperature, a signature of Fermi surface reconstruction caused by stripe order. Tracking the height of the upturn as it decreases with doping enables us to pin down the precise location of the QCP where stripe order ends, at p* = 0.235 +- 0.005. We propose that the temperature T_(rho) below which the upturn begins marks the onset of the pseudogap phase, found to be roughly twice as high as the stripe ordering temperature in this material.
@article{arxiv.0909.4218,
title = {Zooming on the Quantum Critical Point in Nd-LSCO},
author = {Olivier Cyr-Choinière and R. Daou and J. Chang and Francis Laliberté and Nicolas Doiron-Leyraud and David LeBoeuf and Y. J. Jo and L. Balicas and J. -Q. Yan and J. -G. Cheng and J. -S. Zhou and J. B. Goodenough and Louis Taillefer},
journal= {arXiv preprint arXiv:0909.4218},
year = {2010}
}
Comments
Submitted for the Proceedings of the M2S-IX Conference (Tokyo, September 2009)