Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 52: Quantum Impurities and Kondo Physics

TT 52.8: Vortrag

Donnerstag, 4. April 2019, 11:30–11:45, H7

Many-body approach to Luttinger’s theorem of the Kondo lattice — •Steffen Sykora¹ and Klaus W. Becker² — ¹IFW Dresden, 01069 Dresden, Germany — ²Institut für Theoretische Physik, TU Dresden, 01062 Dresden, Germany

A numerical verification of Luttinger’s theorem, based on a recently developed many-body approach, is given for the Kondo-lattice model. For a two-dimensional lattice the completely localized spins (S=1/2) are found to contribute to the Fermi sea volume as if they were electrons, which is in agreement with Oshikawa’s topological proof of Luttinger’s theorem. Underpinning this result we show results of the momentum-resolved one-particle spectral function where nearly dispersionless excitations appear clearly below the Fermi level for different values of the conduction electron filling. Numerical integration over momentum and energy always leads to the correct particle number of the localized spins according to the well-accepted picture of a large Fermi surface. To our knowledge, the present study is the first many-body approach, which is able to reproduce the correct value of Luttinger’s theorem for this model.