# Unveiling Quadrupolar Kondo Effect in the Heavy Fermion Superconductor PrV$_2$Al$_{20}$

## TL;DR

This study provides evidence for the quadrupolar Kondo effect driving non-Fermi liquid behavior in the heavy fermion superconductor PrV$_2$Al$_{20}$, revealing complex low-temperature phenomena and deviations from expected scaling.

## Contribution

It offers the first systematic experimental investigation of NFL behavior linked to the quadrupolar Kondo effect in PrV$_2$Al$_{20}$, highlighting deviations at low temperatures.

## Key findings

- Universal scaling behavior consistent with quadrupolar Kondo lattice
- Sign change in magnetoresistance below ~8 K
- Power-law divergence in specific heat at low temperatures

## Abstract

Heavy fermion metals hosting multipolar local moments set a new stage for exploring exotic spin-orbital entangled quantum phases. In such systems, the quadrupolar Kondo effect serves as the key ingredient in the orbital-driven non-Fermi liquid (NFL) behavior and quantum critical phenomena. The cubic heavy fermion superconductor Pr$Tr_2$Al$_{20}$ ($Tr$: Ti, V) is a prime candidate for realizing the quadrupolar Kondo lattice. Here, we present a systematic study of the NFL phenomena in PrV$_2$Al$_{20}$ based on magnetoresistance (MR), magnetic susceptibility and specific heat measurements. Upon entering the NFL regime, we observe a universal scaling behavior expected for the quadrupolar Kondo lattice in PrV$_2$Al$_{20}$, which indicates a prominent role of the quadrupolar Kondo effect in driving the NFL behavior. Deviations from this scaling relation occur below $\sim 8$ K, accompanied by a sign change in the MR and a power-law divergence in the specific heat. This anomalous low-temperature state points to the presence of other mechanisms which are not included in the theory, such as heavy fermion coherence or multipolar quantum critical fluctuations.