A peak in the critical current for quantum critical superconductors
- 자연과학대학
- Hit2596
- 2018-04-09
A peak in the critical current for quantum critical superconductors
Center for Quantum Materials and Superconductivity(CQMS), Department of Physics, Sungkyunkwan University, Soon-Gil Jung, Soonbeom Seo, Sangyun Lee & Tuson Park
National Research Foundation of Korea announced that Professor Tuson Park and researcher Professor Soon-Gil Jung of Sungkyunkwan University clarified the principle of formation of unsteady superconductors, one of the unsolved problems in solid physics.
[Abstract]
Generally, studies of the critical current Ic are necessary if superconductors are to be of practical use, because Ic 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 Ic, Ic(0), at a hidden quantum critical point (QCP), where a continuous antiferromagnetic transition temperature is suppressed by pressure toward 0 K in CeRhIn5 and 4.4% Sn-doped CeRhIn5. The Ic(0)s of these Ce-based compounds under pressure exhibit a universal temperature dependence, underlining that the peak in zero-field Ic(P) is determined predominantly by critical fluctuations associated with the hidden QCP. The dc conductivity σdc is a minimum at the QCP, showing anti-correlation with Ic(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 Ic, therefore providing a direct link between a QCP and unconventional superconductivity.