Superconductivity and non-Fermi-liquid behavior of Ce2PdIn8

Abstract

The electrical resistivity of the heavy fermion superconductor Ce${}_{2}$PdIn${}_{8}$ was measured in magnetic fields up to 12 T and under hydrostatic pressures up to 21 kbar. At zero field, the low-temperature electrical resistivity in the normal state exhibits a power-law behavior ${\ensuremath{\rho}}_{0}+{\mathit{AT}}^{n}$ with $nl2$. In this non-Fermi-liquid regime, both the superconducting temperature ${T}_{c}$ and the coefficient $\mathrm{A=}$ decrease with increasing pressure, while the exponent $n$ and the resistivity maximum at ${T}_{max}$ increase. The findings indicate a destabilization of the superconducting state via increasing hybridization strength between the 4$f$ and conduction electrons. In concert, enlargement of the $f$-band width at the Fermi level results in a decrease of the density of states $N({E}_{F})$. Application of magnetic fields recovers the Fermi-liquid state at ${H}_{c2}$, at which both $A$ and ${\ensuremath{\rho}}_{0}$ show a tendency to diverge. The data obtained indicate that any change in the Kondo interaction strength in Ce${}_{2}$PdIn${}_{8}$ by applied pressure or quenching spin fluctuations by external magnetic fields results in pushing away the system from the non-Fermi-liquid regime concomitantly with the destruction of the superconducting state. These new results support a scenario in which the superconductivity in Ce${}_{2}$PdIn${}_{8}$ is driven by antiferromagnetic spin fluctuations in the vicinity of an underlying quantum critical point.