Quantum Critical Scaling and origin of Non-Fermi-Liquid behavior in Sc$_{1-x}$U$_{x}$Pd$_3$

TL;DR

This study reveals that magnetic excitations in Sc$_{1-x}$U$_{x}$Pd$_3$ near the quantum critical point exhibit $\,\omega/T$ scaling, suggesting a universal origin of non-Fermi-liquid behavior in f-electron materials related to quantum phase transitions.

Contribution

It demonstrates that $\,\omega/T$ scaling occurs in Sc$_{1-x}$U$_{x}$Pd$_3$ near the QCP, supporting the idea of a universal mechanism for NFL behavior across different f-electron systems.

Findings

Magnetic excitations are spatially incoherent and broad in energy.

$\,\omega/T$ scaling observed at all investigated wave vectors.

NFL behavior linked to quantum critical phenomena regardless of transition type.

Abstract

We use inelastic neutron scattering to study magnetic excitations of Sc$_{1-x}$U$_{x}$Pd$_3$ for U concentrations ($x=0.25$, 0.35) near the spin glass quantum critical point (QCP). The excitations are spatially incoherent, broad in energy ($E=\hbar\omega$), and follow $\omega/T$ scaling at all wave vectors investigated. Since similar $\omega/T$ scaling has been observed for UCu$_{5-x}$Pd$_x$ and CeCu$_{6-x}$Au$_{x}$ near the antiferromagnetic (AF) QCP, we argue that the observed non Fermi liquid (NFL) behavior in these $f$-electron materials arises from the critical phenomena near a T=0 K phase transition, irrespective of the nature of the transition.