E138-02 - Forschungsbereich Correlations: Theory and Experiments
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Journal:
Physical Review Letters
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ISSN:
0031-9007
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Date (published):
29-Mar-2019
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Publisher:
AMER PHYSICAL SOC
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Peer reviewed:
Yes
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Keywords:
exciton condensation; DMFT
en
Abstract:
We present a dynamical mean-field study of dynamical susceptibilities in the two-band Hubbard model. Varying the model parameters we analyze the two-particle excitations in the normal as well as in the ordered phase, an excitonic condensate. The two-particle dynamical mean-field theory spectra in the ordered phase reveal the gapless Goldstone modes arising from spontaneous breaking of continuous symmetries. We also observe the gapped Higgs mode, characterized by vanishing of the gap at the phase boundary. Qualitative changes observed in the spin susceptibility can be used as an experimental probe to identify the excitonic condensation.
