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TT: Fachverband Tiefe Temperaturen
TT 86: Correlated Magnetism – Spin Liquids II
TT 86.2: Vortrag
Donnerstag, 12. März 2026, 15:15–15:30, CHE/0091
Unconventional Spin Dynamics and Supersolid Excitations in the Triangular-Lattice XXZ Model — •Rafael Alvaro Flores Calderon1, Roderich Moessner2, and Frank Pollmann1 — 1Department of Physics, Technical University of Munich, 85748 Garching, Germany — 2Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, D-01187 Dresden, Germany
Motivated by recent experiments, we investigate the spin-1/2 XXZ model on the triangular lattice with strong Ising anisotropy, combining large-scale numerical simulations and analytical methods to uncover unconventional spin dynamics at T=0. First, we compute the dynamical spin structure factor using density matrix renormalization group (DMRG) simulations and find excellent agreement with inelastic neutron scattering data on the layered compound K2Co(SeO3)2. The low-energy spectrum reveals a roton-like minimum at the M point, absent in linear spin-wave theory, accompanied by peak intensity and a broad continuum above it. Near the Γ point, we observe an approximately linear dispersion with vanishing spectral weight. Second, we compare multiple analytical frameworks that reproduce the observed features. Remarkably, a variational supersolid QDM wavefunction and the DMRG ground state exhibit nearly identical structure factors with pronounced transverse photon-like excitations. Together, our comprehensive theoretical and numerical analysis elucidates the microscopic origin of supersolid excitations in the XXZ triangular lattice model and their proximity to a spin liquid phase observed experimentally.
Keywords: Frustrated magnetism; Hard-core bosons; Quantum spin liquid; Quantum spin models; Supersolids