Pairing Correlations Near a Kondo-Destruction Quantum Critical Point

TL;DR

This paper explores how pairing susceptibilities are affected near a Kondo-destruction quantum critical point in heavy-fermion systems, revealing enhanced singlet pairing close to the transition.

Contribution

It demonstrates that antiferromagnetic interimpurity exchange interactions enhance singlet pairing near a Kondo-destruction quantum critical point using advanced computational methods.

Findings

Singlet pairing is enhanced near the quantum critical point.

Kondo-destruction quantum critical point separates Kondo-screened and local-moment phases.

Results have implications for understanding heavy-fermion superconductivity.

Abstract

Motivated by the unconventional superconductivity observed in heavy-fermion metals, we investigate pairing susceptibilities near a continuous quantum phase transition of the Kondo-destruction type. We solve two-impurity Bose-Fermi Anderson models with Ising and Heisenberg forms of the interimpurity exchange interaction using continuous-time quantum Monte-Carlo and numerical renormalization-group methods. Each model exhibits a Kondo-destruction quantum critical point separating Kondo-screened and local-moment phases. For antiferromagnetic interimpurity exchange interactions, singlet pairing is found to be enhanced in the vicinity of the transition. Implications of this result for heavy-fermion superconductivity are discussed.