Kondo destruction Quantum Criticality in Heavy Fermion System

Metallic quantum critical states without well-defined quasiparticles have attracted great interest [1,2]. In heavy fermion metals, two types of quantum criticality are established: (i) Kondo destruction, a beyond-Landau critical point featured by the complete loss of quasiparticles [1], and (ii) a fluctuating spin-density-wave (SDW) type within the Landau framework. Using extended dynamical mean-field theory with continuous-time quantum Monte Carlo, we show that even for the SDW case, the upper cutoff of Landau criticality lies well below the bare Kondo scale due to the dynamical competition between RKKY and Kondo interactions [3]. This yields a broad regime dominated by Kondo-destruction–type fluctuations, motivating the notion of SDWr quantum criticality. The resulting quasiparticle breakdown accounts for strange-metal behavior and provides a natural route to unconventional superconductivity, offering a unified framework that covers the heavy fermion superconductor  CeCu2Si2 and related systems.

 

 

[1] H. Hu, L. Chen, Q. Si, Nat. Phys. 20, 1863–1873 (2024)

 

[2] S. Paschen & Q. Si, Nat. Rev. Phys. 3, 9 (2021). Q. Si et al., Nature 413, 804 (2001); S. Kirchner et al., RMP 92, 011002 (2020).

 

[3] L. Chen, Y. Fang, Y. Wang, H. Hu, A. Cai, Q. Si, unpublished (2025).

 

[4] H. Hu, et al., arXiv:2109.13224 (2021).