Fermi surface reconstruction and strange metal behavior at a heavy fermion quantum phase transition

Professor Jan von Delft and his team address the sudden reconstruction of the Fermi surface (FS) at the Kondo breakdown (KB) quantum critical point (QCP) in heavy fermion systems. They focus on results on the periodic Anderson model, obtained using a two-site cellular dynamical mean-field theory (CDMFT) approach. By employing the Numerical Renormalization Group to solve the effective impurity model, they are able to dispose of the limitations faced by previous two-site CDMFT studies. At zero temperature, we find a continuous KB-QCP separating two Fermi liquid phases, which differ in their FS volumes. The Fermi liquid scale decreases towards and vanishes at the KB-QCP, giving rise to a non-Fermi liquid quantum critical regime at intermediate temperatures. They discuss several aspects of the KB-QCP and the physics in its vicinity. This includes new results on the FS reconstruction, which is accompanied by the emergence of a Luttinger surface hosting Luttinger quasiparticles; and on the non-Fermi liquid regime, which shows strange metal behavior beyond the marginal Fermi liquid paradigm, including a linear-in-T resistivity and dynamical scaling of the optical conductivity, in good agreement with recent experiments.

 

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