Evidence for Competition between Superconductivity and Kondo Effect in CeFeAsO0.7F0.3 under High Pressure

Abstract

We discover a pressure induced quantum phase transition from the superconducting state to the non-superconducting Kondo screened phase associated with a 2% volume collapse in CeFeAsO0.7F0.3 through measurements of high-pressure resistance, synchrotron x-ray diffraction, and x-ray absorption spectroscopy (XAS) in a diamond anvil cell. Our XAS data of Ce-L3 in CeFeAsO0.7F0.3 clearly show a spectral weight transfer from the main line to the satellite line after the transition, demonstrating the formation of the Kondo singlets under pressure in CeFeAsO1-xFx. Our results have revealed a physical picture of a pressure-induce competition between Kondo singlets and BCS singlets in the Ce-pnictide superconductors.

18 pages, 5 figures

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Cited by in corpus (4)

• Vortex dynamics and irreversibility line in optimally doped SmFeAsO${}_{0.8}$F${}_{0.2}$ from ac susceptibility and magnetization measurements
• Superconductivity under pressure in $R$FeAsO${}_{1-\mathrm{x}}$F${}_{\mathrm{x}}$ ($R$=La, Ce$-$Sm) by dc magnetization measurements
• Doping dependence of the upper critical field, superconducting current density and thermally activated flux flow activation energy in polycrystalline CeFeAsO1-xFx superconductors
• Hydrostatic and chemical pressure tuning of CeFeAs_1-xP_xO single crystals