Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 2: Correlated Electrons: Electronic Structure Calculations and Other Theoretical Topics
TT 2.11: Vortrag
Montag, 1. April 2019, 12:15–12:30, H7
From gapped Goldstone to Higgs modes in excitonic magnets — •Jan Kuneš1, Dominique Geffroy1,2, Josef Kaufmann1, Atsushi Hariki1, Andreas Hausoel3, and Patrik Gunacker1 — 1TU Wien, Austria — 2Masaryk University, Brno, Czechia — 3Univesity of Würzburg, Germany
We present a dynamical mean-field study of dynamical susceptibility in two-orbital Hubbard model across the exciton condensation transition. We observe appearance of Goldstone modes consistent with the broken symmetries. Reducing continuously the symmetry of the Hamiltonian we open gaps in the Goldstone modes. Upon increasing the amplitude of the symmetry breaking terms the character of the gapped modes smoothly changes from gapped Goldstone modes to Higgs amplitude fluctuations. Another notable observation is a qualitative change of the dynamical spin structure factor upon exciton condensation, which may be used as an experimentally accessible probe of the spin-triplet exciton condensate.
Geffroy et al., arXiv:1808.08046