Small-to-large Fermi surface fluctuations in heavy fermion systems I: Dynamical scaling

Studies in heavy fermion systems have led to the notion of Kondo destruction. It characterizes a beyond-Landau quantum critical point, across which the Fermi surface goes from “large” to “small” [1]. An important signature of the Kondo destruction quantum criticality appears in the anomalous dynamical critical properties, as studied  in Kondo lattice models by extended dynamical mean-field theory (EDMFT) [1,2], with fractional exponent and E/T scaling [3].  Here we carry out the first cluster-EDMFT analysis of an Anderson lattice model. We show that, for both Ising-anisotropic and SU(2)-symmetric models, the Kondo destruction captures the anomalous dynamical scaling in a robust way [4]. Implications of our results for unconventional superconductivity in these systems [4] will be discussed in the next talk.

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

[2] H. Hu, A. Cai, Q. Si, arXiv:2004.04679 (2020).

[3] A. Schroeder et al., Nature 407, 351 (2000).

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