Regensburg 2022 – scientific programme
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MA: Fachverband Magnetismus
MA 35: Poster 2
MA 35.44: Poster
Thursday, September 8, 2022, 16:00–18:00, P4
Spin Excitations, Accidental Soft Modes, and Phase Diagram of the Triangular-Lattice t-t′-U Hubbard Model — •Josef Willsher1, Hui-Ke Jin1, and Johannes Knolle1,2,3 — 1TUM, Munich, Germany — 2MCQST, Munich, Germany — 3Imperial College London, London, UK
The structure factor is an important probe of quantum magnets but due to numerical limitations it remains a challenge to make theoretical predictions beyond linear spin wave calculations of Heisenberg-like models. In this work we study the excitation spectrum of the triangular lattice Hubbard model including next-nearest neighbour hopping within a self-consistent random phase approximation. Starting from the 120-degree and stripe magnetic orders we compute the relevant magnon spectra and discuss connections to recent experiments on triangular lattice compounds. In addition, we show that the condensation of accidental soft-modes allows us to construct the phase diagram of the model, which is consistent with previous results of the variational cluster approximation. We discuss the implications of our findings for unconventional magnon spectra and even for the presence of quantum disordered phases without long range order.