Interplay of spin gap and nanoscopic quantum fluctuations in intermetallic CeCu2Ge2

TL;DR

This study uses neutron scattering to explore how a field-induced spin gap interacts with quantum fluctuations in CeCu2Ge2, revealing insights into quantum criticality and its relation to unconventional superconductivity in heavy electron systems.

Contribution

It demonstrates the development of a spin gap near the quantum critical point and links it to quantum fluctuations, offering new understanding of their interplay in heavy electron materials.

Findings

Spin gap of 0.56 meV develops near the critical field of 8 T.

The spin gap is driven by fluctuations of the antiferromagnetic order.

The spin gap's behavior correlates with superconducting transition temperatures.

Abstract

Neutron scattering measurements are used to elucidate interplay of the field-induced spin gap and the quantum fluctuations in archetypal heavy electron system CeCu$_{2}$Ge$_{2}$. A spin gap of $\Delta$ = 0.56 meV is found to develop near the field-induced quantum critical state at $H$$_{c}$$\simeq$ 8 T, driven by fluctuations of the long range antiferromagnetic order parameter. The superconducting transition temperature in many magnetic superconductors is found to exhibit one-to-one correspondence with the spin gap. In this regard, the demonstration of an interplay of the spin gap with the nanoscopic dynamic correlation provides new arena to explore direct relation between the quantum critical behavior and the unconventional superconductivity, especially in heavy electrons systems.