The effective increase in atomic scale disorder by doping and superconductivity in Ca${}_3$Rh${}_4$Sn${}_{13}$

Abstract

The comprehensive research of the electronic structure, thermodynamic and electrical transport properties reveals the existence of inhomogeneous superconductivity due to structural disorder in Ca${}_3$Rh${}_4$Sn${}_{13}$ doped with La (Ca${}_{3-x}$La${}_x$Rh${}_4$Sn${}_{13}$) or Ce (Ca${}_{3-x}$Ce${}_x$Rh${}_4$Sn${}_{13}$) with superconducting critical temperatures $T_c^{\star }$ higher than those ($T_c$) observed in the parent compounds. The $T-x$ diagrams and the entropy $S(x{)}_T$ isotherms well document the relation between degree of an atomic disorder and separation of the {\it high-temperature} $T_c^{\star }$ and $T_c$-bulk phases. In these dirty superconductors with the mean free path much smaller than the coherence length, the Werthamer-Helfand-Hohenber theoretical model does not well fits the $H_{c2}(T)$ data. We suggest that this can result from two-band superconductivity or from the presence of strong inhomogeneity in these systems. The multiband model very well describes the $H-T$ dependencies, but the present results as well as our previous studies give arguments for the scenario based on the presence of nanoscopic inhomogeneity of the superconducting state. We also revisited the nature of structural phase transition at $T^{\star }\sim 130-170$ K and documented that there might be another precursor transition at higher temperatures. The impact of the magnetic Ce-Ce correlations on the increase of $T_c$ in respect to the critical temperatures of Ca${}_{3-x}$La${}_x$Rh${}_4$Sn${}_{13}$ is also discussed.

20 pages, revtex

References in corpus (14)

• Ambient Pressure Structural Quantum Critical Point in the Phase Diagram of (Ca${}_x$Sr${}_{1-x}$)${}_3$Rh${}_4$Sn${}_{13}$
• Dynamical charge density waves rule the phase diagram of cuprates
• Superconductivity of La${}_3$Co${}_4$Sn${}_{13}$ and La${}_3$Rh${}_4$Sn${}_{13}$: A comparative study
• Thermodynamic transitions in inhomogeneous d-wave superconductors
• Crystal structure and phonon softening in Ca3Ir4Sn13
• Unconventional charge-density wave in Sr3Ir4Sn13 cubic superconductor revealed by optical spectroscopy study
• Double superconducting transition in the filled skutterudite PrOs4Sb12 and sample characterizations
• Superconductivity in the presence of disorder in skutterudite-related La${}_3$Co${}_4$Sn${}_{13}$ and La${}_3$Ru${}_4$Sn${}_{13}$ compounds; electrical transport and magnetic studies
• Second-order Structural Transition in Superconductor La${}_3$Co${}_4$Sn${}_{13}$
• Pressure-Induced Phase Transition in La${}_{1-x}$Sm${}_x$O${}_{0.5}$F${}_{0.5}$BiS${}_2$
• Soft phonon modes in the vicinity of the structural quantum critical point
• Effect of atomic disorder and Ce doping on superconductivity of Ca3Rh4Sn13: Electric transport properties under high pressure
• Optical spectroscopy study of charge density wave order in Sr${}_3$Rh${}_4$Sn${}_{13}$ and (Sr${}_{0.5}$Ca${}_{0.5}$)${}_3$Rh${}_4$Sn${}_{13}$
• Experimental Determination of the Fermi Surface of Sr3Ir4Sn13

Cited by in corpus (1)

• Possible unconventional pairing in $(\text{Ca,Sr}{)}_3(\text{Ir,Rh}{)}_4{\text{Sn}}_{13}$ superconductors revealed by controlling disorder