Doublon-Holon Origin of the Subpeaks at the Hubbard Band Edges

Dynamical mean-field theory (DMFT) studies frequently observe a fine structure in the local spectral function of the SU(2) Fermi-Hubbard model at half filling: In the metallic phase close to the Mott transition, subpeaks emerge at the inner edges of the Hubbard bands. Here we demonstrate that these...

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Bibliographic Details
Published in:Physical review letters 2017-12, Vol.119 (23), p.236402-236402, Article 236402
Main Authors: Lee, Seung-Sup B, von Delft, Jan, Weichselbaum, Andreas
Format: Article
Language:English
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Summary:Dynamical mean-field theory (DMFT) studies frequently observe a fine structure in the local spectral function of the SU(2) Fermi-Hubbard model at half filling: In the metallic phase close to the Mott transition, subpeaks emerge at the inner edges of the Hubbard bands. Here we demonstrate that these subpeaks originate from the low-energy effective interaction of doublon-holon pairs, by investigating how the correlation functions of doublon and holon operators contribute to the subpeaks. A mean-field analysis of the low-energy effective Hamiltonian provides results consistent with our DMFT calculation using the numerical renormalization group as an impurity solver. In the SU(3) and SU(4) Hubbard models, the subpeaks become more pronounced due to the increased degeneracy of doublon-holon pair excitations.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.119.236402