Archive ouverte HAL – Fermi surface enlargement on the Kondo lattice

Eoin Quinn 1 Onur Erten

Eoin Quinn, Onur Erten. Fermi surface enlargement on the Kondo lattice. Physical Review B : Condensed matter and materials physics, American Physical Society, 2019, 99 (24), ⟨10.1103/PhysRevB.99.245123⟩. ⟨hal-02291818⟩

The Kondo lattice model is a paradigmatic model for the description of local moment systems, a class of materials exhibiting a range of strongly correlated phenomena including heavy fermion formation, magnetism, quantum criticality and unconventional superconductivity. Conventional theoretical approaches invoke fractionalization of the local moment spin through large-N and slave particle methods. In this work we develop a new formalism, based instead on non-canonical degrees of freedom. We demonstrate that the graded Lie algebra su(2|2) provides a powerful means of organizing correlations on the Kondo lattice through a splitting of the electronic degree of freedom, in a manner which entwines the conduction electrons with the local moment spins. This offers a novel perspective on heavy fermion formation. Unlike slave-particle methods, non-canonical degrees of freedom generically allow for a violation of the Luttinger sum rule, and we interpret recent angle resolved photoemission experiments on Ce-115 systems in view of this.

  • 1. LPTMS - Laboratoire de Physique Théorique et Modèles Statistiques