Zero-Field Ambient-Pressure Quantum Criticality in the Stoichiometric Non-Fermi Liquid System CeRhBi

TL;DR

This study reveals that the stoichiometric heavy fermion compound CeRhBi exhibits quantum critical behavior at ambient pressure and zero magnetic field, characterized by E/T scaling and local criticality, providing a new model for understanding non-Fermi liquid states.

Contribution

It demonstrates quantum criticality in a stoichiometric system without tuning parameters, using neutron scattering and muSR to reveal local critical behavior and E/T scaling.

Findings

Evidence of E/T scaling in spin dynamics

Observation of local quantum criticality

Non-Fermi liquid behavior at ambient conditions

Abstract

The strange electronic state of a class of materials which violates the predictions of conventional Fermi-liquid theory of metals remains enigmatic. Proximity to a quantum critical point is a possible origin of this non-Fermi liquid (NFL) behavior, which is usually accomplished by tuning the ground state with non-thermal control parameters such as chemical composition, magnetic field or pressure. We present the spin dynamics study of a stoichiometric NFL system CeRhBi, using low-energy inelastic neutron scattering (INS) and muon spin relaxation (muSR) measurements. It shows evidence for an energy-temperature (E/T) scaling in the INS dynamic response and a time-field scaling of the muSR asymmetry function indicating a quantum critical behavior in this compound. The E/T scaling reveals a local character of quantum criticality consistent with the power-law divergence of the magnetic susceptibility, logarithmic divergence of the magnetic heat capacity and T-linear resistivity at low temperature. The NFL behavior and local criticality occur over a very wide dynamical range at zero field and ambient pressure without any tuning in this stoichiometric heavy fermion compound is striking, making CeRhBi an exemplary model system amenable to in-depth studies for quantum criticality.