Dresden 2020 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 46: Poster Session: Frustrated Magnets, Quantum Magnets, Charge Order and Complex Oxids

TT 46.12: Poster

Mittwoch, 18. März 2020, 15:00–19:00, P2/2OG

Frustrated quantum magnetism in the Kondo lattice on the zig-zag ladder — •Cassian Plorin, Lena-Marie Woelk, Matthias Peschke, and Michael Potthoff — I. Institut für Theoretische Physik, Fachbereich Physik, Universität Hamburg

We study the phase diagram of the one-dimensional Kondo lattice model with nearest-neighbor hopping t1 and next-nearest-neighbor hopping t2 at half-filling using matrix-product-states techniques. Of particular interest is the interplay between geometric frustration, antiferromagnetic ordering of the localized spins, and the Kondo effect.

It is shown that t2 can induce various magnetic phases such as spin dimerization, quasi-long-range spin-spiral order and short-range incommensurate spin-spiral order – strongly depending on the Kondo exchange coupling JK. In the strong-JK regime, the appearance of short-range magnetic order can be explained by perturbative techniques.

The same model but with classical localized spins is investigated as well. Here, we find a qualitatively similar ground-state phase diagram.

In addition we discuss the spin-only Kondo-necklace model on the zig-zag ladder, which can be seen as an effective theory of the correlated Kondo lattice in the U→∞ limit. Here, the intriguing question is how the critical point of the J1-J2 spin chain affects the phase diagram and whether or not this is linked to the U=0 Kondo lattice.

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