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TT: Fachverband Tiefe Temperaturen

TT 56: CE: Heavy Fermions

TT 56.3: Vortrag

Donnerstag, 17. März 2011, 17:00–17:15, HSZ 105

Interplay between Kondo effects in a Kondo lattice with two in-equivalent local moments — •Adel Benlagra¹, Lars Fritz², and Matthias Vojta¹ — ¹Institut für Theoretische Physik, TU Dresden, Germany — ²Institut für Theoretische Physik, Universität zu Köln, Germany

Usual theoretical studies of Kondo systems often assume the presence of a single spin−1/2 local moment per unit cell and little is known about the behavior of a Kondo lattice with multiple distinct local moments. Motivated by the recently studied family of ternary compounds (RE)₃Pd₂₀X₆ (Re=rare-earth, X=Ge, Si), which have two in-equivalent Kondo sites per unit cell, we study a Kondo lattice Hamiltonian with two local moments coupled to the sea of conduction electrons with different Kondo couplings (J₂<J₁). In particular, we investigate the interplay between the resulting Kondo screenings and explore the thermodynamic properties of the heavy Fermi liquid regime using slave bosons in the mean-field approximation. It is found that the two effects compete or cooperate depending on the electronic filling number. The coherence scale governing the low temperature behavior of the heavy Fermi liquid is affected and, in particular, its ratio to the Kondo scales is not generically independent of the Kondo couplings as is the case for the standard Kondo lattice problem.