A peak in the critical current for quantum critical superconductors.
basic_science · Level V
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- Record sourced from PubMed, PMID 29382852.
- Also identified by DOI 10.1038/s41467-018-02899-5 and PMC identifier 5789853.
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Abstract
Generally, studies of the critical current I<sub>c</sub> are necessary if superconductors are to be of practical use, because I<sub>c</sub> sets the current limit below which there is a zero-resistance state. Here, we report a peak in the pressure dependence of the zero-field I<sub>c</sub>, I<sub>c</sub>(0), at a hidden quantum critical point (QCP), where a continuous antiferromagnetic transition temperature is suppressed by pressure toward 0 K in CeRhIn<sub>5</sub> and 4.4% Sn-doped CeRhIn<sub>5</sub>. The I<sub>c</sub>(0)s of these Ce-based compounds under pressure exhibit a universal temperature dependence, underlining that the peak in zero-field I<sub>c</sub>(P) is determined predominantly by critical fluctuations associated with the hidden QCP. The dc conductivity σ<sub>dc</sub> is a minimum at the QCP, showing anti-correlation with I<sub>c</sub>(0). These discoveries demonstrate that a quantum critical point hidden inside the superconducting phase in strongly correlated materials can be exposed by the zero-field I<sub>c</sub>, therefore providing a direct link between a QCP and unconventional superconductivity.