Charge gap and charge redistribution among copper and oxygen orbitals in the normal state of the Emery model

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Main Authors: Reaney, G. L., Kowalski, N., Tremblay, A. -M. S., Sordi, G.
Format: Preprint
Published: 2025
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author Reaney, G. L.
Kowalski, N.
Tremblay, A. -M. S.
Sordi, G.
author_facet Reaney, G. L.
Kowalski, N.
Tremblay, A. -M. S.
Sordi, G.
contents Unraveling the behavior of the electrons in the copper-oxygen planes of cuprate superconductors remains a challenge. Here we examine the electronic charge redistribution among planar copper and oxygen orbitals and the charge gap using the Emery model in the normal state, solved with cellular dynamical mean-field theory at finite temperature. We quantify the charge redistribution as a function of the onsite Coulomb repulsion on the copper orbitals, the bare copper-oxygen energy difference, and the hole or electron doping. We find that the position relative to the metal to insulator boundary of the Zaanen-Sawatzky-Allen diagram determines the charge redistribution among copper and oxygen orbitals. For a fixed bare Cu-O energy difference, an increase in the Cu electron repulsion leads to a transfer of the electronic charge from Cu to O orbitals. For a fixed charge gap size of the undoped state, as the system evolves from a charge-transfer to a Mott-Hubbard regime, the electronic charge is transferred from Cu to O orbitals. Our findings posit the Coulomb repulsion and the bare charge-transfer energy as key drivers of the microscopic process of charge redistribution in the CuO$_2$ plane. They quantify the anticorrelation between the charge gap size and oxygen hole content. They show that for fixed band-structure parameters, the charge gap and the charge redistribution between Cu and O orbitals provide a way to understand observed trends in cuprates.
format Preprint
id arxiv_https___arxiv_org_abs_2505_11161
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Charge gap and charge redistribution among copper and oxygen orbitals in the normal state of the Emery model
Reaney, G. L.
Kowalski, N.
Tremblay, A. -M. S.
Sordi, G.
Strongly Correlated Electrons
Superconductivity
Unraveling the behavior of the electrons in the copper-oxygen planes of cuprate superconductors remains a challenge. Here we examine the electronic charge redistribution among planar copper and oxygen orbitals and the charge gap using the Emery model in the normal state, solved with cellular dynamical mean-field theory at finite temperature. We quantify the charge redistribution as a function of the onsite Coulomb repulsion on the copper orbitals, the bare copper-oxygen energy difference, and the hole or electron doping. We find that the position relative to the metal to insulator boundary of the Zaanen-Sawatzky-Allen diagram determines the charge redistribution among copper and oxygen orbitals. For a fixed bare Cu-O energy difference, an increase in the Cu electron repulsion leads to a transfer of the electronic charge from Cu to O orbitals. For a fixed charge gap size of the undoped state, as the system evolves from a charge-transfer to a Mott-Hubbard regime, the electronic charge is transferred from Cu to O orbitals. Our findings posit the Coulomb repulsion and the bare charge-transfer energy as key drivers of the microscopic process of charge redistribution in the CuO$_2$ plane. They quantify the anticorrelation between the charge gap size and oxygen hole content. They show that for fixed band-structure parameters, the charge gap and the charge redistribution between Cu and O orbitals provide a way to understand observed trends in cuprates.
title Charge gap and charge redistribution among copper and oxygen orbitals in the normal state of the Emery model
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2505.11161