Signatures of metal to insulator crossover in the repulsive Fermi Hubbard model through static correlations

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Hauptverfasser: Roy, Sayantan, Pervaiz, Sameed, Paiva, Thereza, Trivedi, Nandini
Format: Preprint
Veröffentlicht: 2024
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author Roy, Sayantan
Pervaiz, Sameed
Paiva, Thereza
Trivedi, Nandini
author_facet Roy, Sayantan
Pervaiz, Sameed
Paiva, Thereza
Trivedi, Nandini
contents Cold atom systems provide a rich platform to realize strongly interacting condensed matter systems, and recent progress in fluorescence imaging technique has enabled identification of nontrivial doublon, singlon, and holon correlation functions. We show that these correlators can be used to identify the conditions under which local moments form in an interacting electronic system. Toward this end, we report a Determinantal Quantum Monte Carlo (DQMC) study of such correlation functions in the two-dimensional repulsive Fermi Hubbard model on a square lattice as a function of doping, interaction strength and temperature. We find definite signatures of the crossover from small U(band regime) to large U(correlated insulator regime). Our key findings are: (1) An opening of a charge gap in the thermodynamic density of states is accompanied by the appearance of temperature insensitive points in the equation of state at finite doping, which can be used to distinguish the band regime in cold atom experiments. (2) Nearest neighbor doublon holon correlations track the opening of charge gap; these compete with density correlations to generate moment moment correlations that show different behavior in the metallic and correlated insulator regime. (3) Non local correlation functions can be used to distinguish between the two regimes, both at and away from half filling. Our results allow comparisons of different correlation functions with recent experimental findings and guide further experimental investigations.
format Preprint
id arxiv_https___arxiv_org_abs_2403_13054
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Signatures of metal to insulator crossover in the repulsive Fermi Hubbard model through static correlations
Roy, Sayantan
Pervaiz, Sameed
Paiva, Thereza
Trivedi, Nandini
Strongly Correlated Electrons
Quantum Gases
Cold atom systems provide a rich platform to realize strongly interacting condensed matter systems, and recent progress in fluorescence imaging technique has enabled identification of nontrivial doublon, singlon, and holon correlation functions. We show that these correlators can be used to identify the conditions under which local moments form in an interacting electronic system. Toward this end, we report a Determinantal Quantum Monte Carlo (DQMC) study of such correlation functions in the two-dimensional repulsive Fermi Hubbard model on a square lattice as a function of doping, interaction strength and temperature. We find definite signatures of the crossover from small U(band regime) to large U(correlated insulator regime). Our key findings are: (1) An opening of a charge gap in the thermodynamic density of states is accompanied by the appearance of temperature insensitive points in the equation of state at finite doping, which can be used to distinguish the band regime in cold atom experiments. (2) Nearest neighbor doublon holon correlations track the opening of charge gap; these compete with density correlations to generate moment moment correlations that show different behavior in the metallic and correlated insulator regime. (3) Non local correlation functions can be used to distinguish between the two regimes, both at and away from half filling. Our results allow comparisons of different correlation functions with recent experimental findings and guide further experimental investigations.
title Signatures of metal to insulator crossover in the repulsive Fermi Hubbard model through static correlations
topic Strongly Correlated Electrons
Quantum Gases
url https://arxiv.org/abs/2403.13054