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TT: Fachverband Tiefe Temperaturen

TT 65: Frustrated Magnets: General I

TT 65.10: Vortrag

Donnerstag, 21. März 2024, 12:00–12:15, H 2053

Spin-1/2 Heisenberg diamond-like decorated honeycomb lattice in a magnetic field from the perspective of localized magnons and exact diagonalization — •Katarína Karľová¹, Jozef Strečka², Malo Rouxel¹, and Andreas Honecker¹ — ¹Laboratoire de Physique Théorique et Modélisation, CNRS UMR 8089, CY Cergy Paris Université, France — ²Department of Theoretical Physics and Astrophysics, P.J. Šafárik University, Košice, Slovakia

The spin-1/2 quantum Heisenberg model on a two-dimensional diamond-like decorated honeycomb lattice is investigated by combining the analytical and numerical methods. The ground-state phase diagram of the investigated model includes besides fully polarized state, monomer-dimer phase, ferrimagnetic phase of Lieb-Mattis type, spin canted phase with a continuously rise of the magnetization with increasing of the magnetic field and macroscopically degenerate dimer-tetramer phase. It is shown that the localized-magnon approach based on a simple classical lattice-gas model of hard-core monomers provides a proper description of low-temperature magnetism and magneto-thermodynamics of the investigated frustrated quantum spin system in a highly frustrated parameter region. The results obtained from the localized-magnon approach are corroborated by the exact numerical diagonalization of small-size systems as well as the density-matrix renormalization group calculations.

Keywords: Heisenberg decorated honeycomb lattice; localized magnon theory; exact diagonalization; magnetization; magnetocaloric effect