Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 65: Frustrated Magnets: General I
TT 65.12: Talk
Thursday, March 21, 2024, 12:30–12:45, H 2053
Quantum phases of the XXZ model with repulsive dipolar Ising interactions on two-dimensional lattices — •Jan Alexander Koziol1, Giovanna Morigi2, and Kai Phillip Schmidt1 — 1Department of Physics, Staudtstraße 7, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany — 2Theoretical Physics, Saarland University, Campus E2.6, D-66123 Saarbrücken, Germany
We analyse the ground-state quantum phase diagram of the XXZ model with repulsive dipolar Ising interactions on two-dimensional lattices. The ground state results from the interplay between the lattice geometry and the long-range interactions, which we account for by means of a classical spin mean-field approach. This extended classical spin mean-field theory accounts for the long-range Ising interaction without truncation. The mean-field analysis is limited by the size of the considered unit cells. We consider three different lattice geometries: square, honeycomb, and triangular. In the limit of zero XY-interactions the ground state is always a devil’s staircase of solid (gapped) phases. Such crystalline phases with broken translational symmetry are robust with respect to finite hopping amplitudes. At intermediate XY-interactions, these gapped phases melt, giving rise to various lattice supersolid phases, which can have exotic features with multiple sublattice densities. Our results are of immediate relevance for experimental realisations of self-organised crystalline ordering patterns, e.g., with ultracold dipolar atoms in an optical lattice.
Keywords: Bose-Hubbard model; XXZ spin model; long-range interaction; dipolar interaction; mean-field