Ground state and excitations of quasiperiodic 1D narrow-band moiré systems: a mean field approach

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Main Authors: Sobrosa, Nicolau, Gonçalves, Miguel, Amorim, Bruno, Castro, Eduardo V., Ribeiro, Pedro
Format: Preprint
Published: 2025
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author Sobrosa, Nicolau
Gonçalves, Miguel
Amorim, Bruno
Castro, Eduardo V.
Ribeiro, Pedro
author_facet Sobrosa, Nicolau
Gonçalves, Miguel
Amorim, Bruno
Castro, Eduardo V.
Ribeiro, Pedro
contents We demonstrate that a mean field approximation can be confidently employed in quasiperiodic moiré systems to treat interactions and quasiperiodicity on equal footing. We obtain the mean field phase diagram for an illustrative one-dimensional moiré system that exhibits narrow bands and a regime with non-interacting multifractal critical states. By systematically comparing our findings with existing exact results, we identify the regimes where the mean field approximation provides an accurate description. Interestingly, in the critical regime, we obtain a quasifractal charge density wave, consistent with the exact results. To complement this study, we employ a real-space implementation of the time-dependent Hartree-Fock, enabling the computation of the excitation spectrum and response functions at the RPA level. These findings indicate that a mean field approximation to treat systems hosting multifractal critical states, as found in two-dimensional quasiperiodic moiré systems, is an appropriate methodology.
format Preprint
id arxiv_https___arxiv_org_abs_2510_04132
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Ground state and excitations of quasiperiodic 1D narrow-band moiré systems: a mean field approach
Sobrosa, Nicolau
Gonçalves, Miguel
Amorim, Bruno
Castro, Eduardo V.
Ribeiro, Pedro
Strongly Correlated Electrons
Disordered Systems and Neural Networks
We demonstrate that a mean field approximation can be confidently employed in quasiperiodic moiré systems to treat interactions and quasiperiodicity on equal footing. We obtain the mean field phase diagram for an illustrative one-dimensional moiré system that exhibits narrow bands and a regime with non-interacting multifractal critical states. By systematically comparing our findings with existing exact results, we identify the regimes where the mean field approximation provides an accurate description. Interestingly, in the critical regime, we obtain a quasifractal charge density wave, consistent with the exact results. To complement this study, we employ a real-space implementation of the time-dependent Hartree-Fock, enabling the computation of the excitation spectrum and response functions at the RPA level. These findings indicate that a mean field approximation to treat systems hosting multifractal critical states, as found in two-dimensional quasiperiodic moiré systems, is an appropriate methodology.
title Ground state and excitations of quasiperiodic 1D narrow-band moiré systems: a mean field approach
topic Strongly Correlated Electrons
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2510.04132