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TT: Fachverband Tiefe Temperaturen
TT 46: Frustrated Magnets: Spin Liquids
TT 46.9: Talk
Thursday, March 30, 2023, 11:45–12:00, HSZ 201
Dynamical signatures of symmetry broken and liquid phases in an S=1/2 Heisenberg antiferromagnet on the triangular lattice — •Markus Drescher1, Laurens Vanderstraeten2, Roderich Moessner3, and Frank Pollmann1,4 — 1TU München, 85748 Garching, Germany — 2University of Ghent, 9000 Gent, Belgium — 3Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden, Germany — 4Munich Center for Quantum Science and Technology, 80799 Munich, Germany
We present the dynamical spin structure factor of the antiferromagnetic spin-1/2 J1−J2 Heisenberg model on a triangular lattice obtained from large-scale matrix-product state simulations. The high frustration due to the combination of antiferromagnetic nearest and next-to-nearest neighbour interactions yields a rich phase diagram. We resolve the low-energy excitations both in the 120∘-ordered phase and in the putative spin liquid phase at J2/J1 = 0.125. In the ordered phase, we observe an avoided decay of the lowest magnon-branch, demonstrating the robustness of this phenomenon in the presence of gapless excitations. Our findings in the spin-liquid phase chime with the field-theoretical predictions for a gapless Dirac spin liquid, in particular the picture of low-lying monopole excitations at the corners of the Brillouin zone. We comment on possible practical difficulties of distinguishing proximate liquid and solid phases based on the dynamical structure factor.