Site-selective correlations in interacting "flat-band" quasicrystals

Fuente: arXiv
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Main Authors: Zhang, Yuxi, Scalettar, Richard T., Fernandes, Rafael M.
Format: Preprint
Published: 2024
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author Zhang, Yuxi
Scalettar, Richard T.
Fernandes, Rafael M.
author_facet Zhang, Yuxi
Scalettar, Richard T.
Fernandes, Rafael M.
contents Model lattices such as the kagome and Lieb lattices have been widely investigated to elucidate the properties of interacting flat-band systems. While a quasicrystal does not have proper bands, the non-interacting density of states of several of them displays the typical signature of a flat band pinned at the Fermi level: a delta-function zero-energy peak. Here, we employ quantum Monte Carlo simulations to determine the effect of onsite repulsion on these quasicrystals. While global properties such as the antiferromagnetic structure factor and the specific heat behave similarly as in the case of periodic lattices undergoing a Mott transition, the behavior of the local density of states depends on the coordination number of the site. In particular, sites with the smallest coordination number, which give the dominant spectral-weight contribution to the zero-energy peak, are the ones most strongly impacted by the interaction. Besides establishing site-selective correlations in quasicrystals, our work also points to the importance of the real-space structure of flat bands in interacting systems.
format Preprint
id arxiv_https___arxiv_org_abs_2410_07894
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Site-selective correlations in interacting "flat-band" quasicrystals
Zhang, Yuxi
Scalettar, Richard T.
Fernandes, Rafael M.
Strongly Correlated Electrons
Model lattices such as the kagome and Lieb lattices have been widely investigated to elucidate the properties of interacting flat-band systems. While a quasicrystal does not have proper bands, the non-interacting density of states of several of them displays the typical signature of a flat band pinned at the Fermi level: a delta-function zero-energy peak. Here, we employ quantum Monte Carlo simulations to determine the effect of onsite repulsion on these quasicrystals. While global properties such as the antiferromagnetic structure factor and the specific heat behave similarly as in the case of periodic lattices undergoing a Mott transition, the behavior of the local density of states depends on the coordination number of the site. In particular, sites with the smallest coordination number, which give the dominant spectral-weight contribution to the zero-energy peak, are the ones most strongly impacted by the interaction. Besides establishing site-selective correlations in quasicrystals, our work also points to the importance of the real-space structure of flat bands in interacting systems.
title Site-selective correlations in interacting "flat-band" quasicrystals
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2410.07894