Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 78: Correlated Electrons: Poster Session

TT 78.40: Poster

Donnerstag, 10. März 2016, 15:00–18:30, Poster D

Dynamical mean-field and density-matrix renormalization-group studies of partial Kondo screening — •Matthias Peschke¹, Maximilian Aulbach¹, Fakher F. Assaad², and Michael Potthoff¹ — ¹I. Institut f. Theor. Physik, Universität Hamburg, Germany — ²Institut f. Theor. Physik und Astrophysik, Universität Würzburg

The competition between Kondo screening and indirect magnetic exchange is studied for systems with geometrical frustration using dynamical mean-field theory (DMFT) and the density-matrix renormalization group (DMRG). A systematic scan of the weak- to intermediate-coupling regime of the periodic Anderson model on the triangular lattice is performed for a wide range of fillings n by means of a site-dependent DMFT approach for a non-primitive unit cell containing three correlated f orbitals. The resulting phase diagram comprises different phases: a non-magnetic Kondo insulator at half-filling, a non-magnetic metallic Kondo-singlet phase for fillings slightly off half-filling and an antiferromagnetic phase at lower fillings driven by RKKY exchange. The antiferromagnetic and the Kondo-singlet phases are separated in the U-n phase diagram by an extended region of partial Kondo screening (PKS), i.e., a phase where the magnetic moment at one site in the unit cell is Kondo screened while the remaining two are coupled antiferromagnetically. The mean-field scenario is checked against numerically exact DMRG data. To this end we analyze different two- and four-point magnetic correlation functions for the Kondo-lattice on one-dimensional frustrated ladders.