Field-induced quantum fluctuations in the heavy fermion superconductor CeCu2Ge2

TL;DR

This paper reports the discovery of a field-tuned quantum critical point in CeCu2Ge2, revealing quantum fluctuations that could be key to understanding unconventional superconductivity in heavy fermion systems.

Contribution

It presents the first observation of a field-induced quantum critical phenomenon in CeCu2Ge2, linking quantum fluctuations to superconductivity in this compound.

Findings

Quantum critical spin fluctuations observed in CeCu2Ge2

Field-tuned quantum critical point identified at specific magnetic fields

Insights into the role of quantum fluctuations in heavy fermion superconductivity

Abstract

Quantum-mechanical fluctuations in strongly correlated electron systems cause unconventional phenomena such as non-Fermi liquid behavior, and arguably high temperature superconductivity. Here we report the discovery of a field-tuned quantum critical phenomenon in stoichiometric CeCu2Ge2, a spin density wave ordered heavy fermion metal that exhibits unconventional superconductivity under ~ 10 GPa of applied pressure. Our finding of the associated quantum critical spin fluctuations of the antiferromagnetic spin density wave order, dominating the local fluctuations due to single-site Kondo effect, provide new information about the underlying mechanism that can be important in understanding superconductivity in this novel compound.