Kondo breakdown and magnetic moment revival in multi-orbital Anderson lattices

Kurzfassung

For decades, heavy Fermion materials at criticality have captivated researchers due to their defiance of Fermi-liquid theory, exhibiting intriguing phenomena such as linear-in-temperature resistivity, Fermi-surface reconstructions, and unconventional energy-over-temperature scaling. Amazingly, these strange metal phenomena manifest across a diverse set of material platforms, including flat band systems and optimally doped transition metal compounds, indicating the existence of a new type of robust quantum phase of matter. In this presentation, we delve into the multi-orbital extension of the periodic Anderson model, which captures the basic properties of heavy Fermion materials. Two critical aspects will be addressed: (I) Demonstrating the existence of a novel critical point associated with Kondo breakdown, characterized by purely local fluctuations arising from destructive hybridization interference. (II) Presenting preliminary findings suggesting the emergence of a new energy scale below the well-known Kondo screening scale. This phenomenon hints at the reemergence of free spin degrees of freedom within the metallic conduction band, and is consistent with the Lieb-Mattis theorem.