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arXiv · 1212.0530

Evidence of a critical hole concentration in underdoped YBa$_2$Cu$_3$O$_y$ single crystals revealed by $^{63}$Cu NMR

S. -H. Baek·T. Loew·V. Hinkov·C. T. Lin·B. Keimer·B. Büchner·H. -J. Grafe
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Abstract

We report a $^{63}$Cu NMR investigation in detwinned YBa$_2$Cu$_3$O$_y$ single crystals, focusing on the highly underdoped regime (y=6.35-6.6). Measurements of both the spectra and the spin-lattice relaxation rates of $^{63}$Cu uncover the emergence of static order at a well-defined onset temperature $T_0$ without a known order parameter as yet. While $T_0$ is rapidly suppressed with increasing hole doping concentration $p$, the spin pseudogap was identified only near and above the doping content at which $T_0\rightarrow 0$. Our data indicate the presence of a critical hole doping $p_c\sim 0.1$, which may control both the static order at $p p_c$.

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S. -H. Baek, T. Loew, V. Hinkov, C. T. Lin, B. Keimer, B. Büchner, H. -J. Grafe. 2012-12-03. Evidence of a critical hole concentration in underdoped YBa$_2$Cu$_3$O$_y$ single crystals revealed by $^{63}$Cu NMR. https://doi.org/10.1103/physrevb.86.220504

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