Broken Time Reversal Symmetry in Superconducting Pr1-xCexPt4Ge12

Abstract

We report results of zero-field muon spin relaxation experiments on the filled-skutterudite superconductors~Pr${}_{1-x}$Ce${}_x$Pt${}_4$Ge${}_{12}$, $x=0$, 0.07, 0.1, and 0.2, to investigate the effect of Ce doping on broken time-reversal symmetry (TRS) in the superconducting state. In these alloys broken TRS is signaled by the onset of a spontaneous static local magnetic field~$B_s$ below the superconducting transition temperature. We find that $B_s$ decreases linearly with $x$ and $\to 0$ at $x\approx 0.4$, close to the concentration above which superconductivity is no longer observed. The (Pr,Ce)Pt${}_4$Ge${}_{12}$ and isostructural (Pr,La)Os${}_4$Sb${}_{12}$ alloy series both exhibit superconductivity with broken TRS, and in both the decrease of $B_s$ is proportional to the decrease of Pr concentration. This suggests that Pr-Pr intersite interactions are responsible for the broken TRS\@. The two alloy series differ in that the La-doped alloys are superconducting for all La concentrations, suggesting that in (Pr,Ce)Pt${}_4$Ge${}_{12}$ pair-breaking by Ce doping suppresses superconductivity. For all $x$ the dynamic muon spin relaxation rate decreases somewhat in the superconducting state. This may be due to Korringa relaxation by conduction electrons, which is reduced by the opening of the superconducting energy gap.

arXiv commentAccepted by Phys. Rev. B

References in corpus (34)

• Time-Reversal Symmetry Breaking Superconductivity in Sr2RuO4
• Enhancement of the upper critical field by nonmagnetic impurities in dirty two-gap superconductors
• Spin-polarized muons in condensed matter physics
• The Challenge of Unconventional Superconductivity
• Phenomenological two-gap model for the specific heat of MgB_2
• Evidence for time-reversal symmetry breaking in the non-centrosymmetric superconductor LaNiC${}_2$
• Time-Reversal Symmetry-Breaking Superconductivity in Heavy Fermion PrOs4Sb12 detected by Muon Spin Relaxation
• Multiple Superconducting Phases in New Heavy Fermion Superconductor PrOs4Sb12
• Observation of broken time-reversal symmetry in the heavy fermion superconductor UPt${}_3$
• Bogoliubov Fermi surfaces in superconductors with broken time-reversal symmetry
• Evidence for Time-Reversal-Symmetry-Broken Superconductivity in Locally Noncentrosymmetric SrPtAs
• Observation of Time-Reversal Symmetry Breaking in the Non-Centrosymmetric Superconductor Re6Zr
• Non-unitary triplet pairing in the centrosymmetric superconductor LaNiGa${}_2$
• Probing the superconducting gap symmetry of PrOs${}_4$Sb${}_{12}$: A penetration depth study
• Superconductivity in the New Platinum Germanides MPt4Ge12 (M = Rare-earth and Alkaline-earth Metals) with Filled Skutterudite Structure
• Evidence for time-reversal symmetry breaking in superconducting PrPt4Ge12
• Absence of zero field muon spin relaxation induced by superconductivity in the B phase of UPt${}_3$
• Superconducting PrOs4Sb12: a thermal conductivity study
• Superfluid Density and Energy Gap-Function of Superconducting PrPt4Ge12
• Weak Interband-Coupling Superconductivity in the Filled Skutterudite LaPt4Ge12
• Pronounced enhancement of the lower critical field and critical current deep in the superconducting state of PrOs${}_4$Sb${}_{12}$
• Three-Dimensional Majorana Fermions in Chiral Superconductors
• Superconducting states in the tetrahedral compound PrOs4Sb12
• Suppression of time reversal symmetry breaking superconductivity in Pr(Os,Ru)_4Sb_12 and (Pr,La)Os_4Sb_12
• Multiband superconductivity in PrPt4Ge12 single crystals
• Time Reversal Symmetry Breaking in the B Phase of the Heavy Fermion Superconductor PrOs${}_4$Sb${}_{12}$
• Triplet superconductivity in the skutterudite PrOs_4Sb_12
• Probing the superconductivity of PrPt4Ge12 through Ce substitution
• Penetration depth, multiband superconductivity, and absence of muon-induced perturbation in superconducting PrOs${}_4$Sb${}_{12}$
• Muon spin relaxation and hyperfine-enhanced 141Pr nuclear spin dynamic in Pr(Os,Ru)4Sb12 and (Pr,La)Os4Sb12
• The Critical Magnetic Field of Anisotropic Two-Band Magnetic Superconductors
• Superconducting gap structure of the skutterudite LaPt4Ge12 probed by specific heat and thermal transport
• Longitudinal muon spin relaxation in high purity aluminum and silver
• Comment on "Pronounced Enhancement of the Lower Critical Field and Critical Current Deep in the Superconducting State of PrOs4Sb12"

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