Pairing correlation near Kondo-destruction quantum criticality*

How quantum criticality affects superconductivity is a central issue in strongly correlated systems. Particularly pressing is for the beyond-Landau quantum criticality, such as appearing in heavy fermion systems in the form of Kondo destruction [1]. In addition, the superconducting Tc in systems such as Ce-115 is high as measured by the Fermi temperature. Thus motivated, we address the pairing instabilities near a Kondo destruction quantum critical point (QCP). We study the cluster Bose-Fermi Anderson model and, using the Cluster Extended-DMFT approach, the Anderson lattice model. We have identified a Kondo destruction QCP between a heavy Fermi liquid and an antiferromagnetic metal phase, and demonstrated enhanced pairing correlations in its vicinity [2]. We also analyze the dependence of this effect on the spin anisotropy. Implications of our results for Ce-115 systems is discussed.

[1] Q. Si and F. Steglich, Science 329, 1161 (2010).
[2] A. Cai et al., to be published.