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arXiv · 1002.2610

Competing orders suppressed by disorder around a hidden quantum critical point in cuprate high Tc superconductors

S. Sanna·F. Coneri. A. Rigoldi·G. Concas·S. Giblin·R. De Renzi
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Abstract

We report extensive muon spin rotation measurements on the lightly doped Y1-xCaxBa2Cu3O6+y compound, which allows us to disentangle the effect of disorder, controlled by random Ca2+ substitution, from that of mere doping. A 3D phase diagram of lightly doped cuprates is accurately drawn, showing that a thermally activated antiferromagnetic phase competes with superconductivity around a quantum critical point, hidden underneath a frozen insulating magnetic state. Disorder suppresses both competing order parameters and unveils the underlying frozen state. Doping and disorder destroy the activated magnetic phase along a line of first order phase transitions that ends at the critical point.

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S. Sanna, F. Coneri. A. Rigoldi, G. Concas, S. Giblin, R. De Renzi. 2010-10-13. Competing orders suppressed by disorder around a hidden quantum critical point in cuprate high Tc superconductors. https://doi.org/10.1103/physrevb.82.100503

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