Non-Fermi liquid normal state of the Heavy Fermion superconductor UBe13

TL;DR

This study investigates the non-Fermi liquid behavior in the normal state of the heavy-fermion superconductor UBe13 through low-temperature specific heat and resistivity measurements, revealing proximity to an antiferromagnetic quantum critical point.

Contribution

It provides experimental evidence of non-Fermi liquid behavior and suggests the existence of a field-induced quantum critical point in UBe13, a novel insight into its quantum phase transitions.

Findings

Resistivity follows T^{3/2} behavior between 4 T and 10 T.

Non-Fermi liquid behavior observed in specific heat data.

Evidence of a nearby antiferromagnetic quantum critical point.

Abstract

Non-Fermi liquid (NFL) behavior in the normal state of the heavy-fermion superconductor UBe13 is studied by means of low-temperature measurements of the specific heat, C, and electrical resistivity, \rho, on a high-quality single crystal in magnetic fields up to 15.5 T. At B=0, unconventional superconductivity forms at Tc=0.9 K out of an incoherent state, characterized by a large and strongly temperature dependent \rho(T). In the magnetic field interval 4 T \leq B \leq 10 T, \rho(T) follows a T^3/2 behavior for Tc(B)\leq T \leq 1 K, while \rho is proportional to T at higher temperatures. Corresponding Non-Fermi liquid behavior is observed in C/T as well and hints at a nearby antiferromagnetic (AF) quantum critical point (QCP) covered by the superconducting state. We speculate that the suppression of short-range AF correlations observed by thermal expansion and specific heat measurements below T_L \simeq 0.7 K (B=0) yields a field-induced QCP, T_L \to 0, at B=4.5 T.