Effect of the Coulomb repulsion and oxygen level on charge distribution and superconductivity in the Emery model for cuprates superconductors

2025/03/10 by St-Cyr, Louis-Bernard, Sénéchal, David
#FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)

paper · doi:10.48550/arxiv.2503.07810

Abstract

The Emery model (aka the three-band Hubbard model) offers a simplified description of the copper-oxide planes that form the building blocks of high-temperature superconductors. By contrast with the even simpler one-band Hubbard model, it differentiates between copper and oxygen orbitals and thus between oxygen occupation (n_p) and copper occupation (n_d). Here we demonstrate, using cluster dynamical mean field theory, how the two occupations are related to the on-site Coulomb repulsion U on the copper orbital and to the energy difference ε_p between oxygen and copper orbitals. Since the occupations (n_p and n_d) have been estimated from NMR for a few materials (LCO, YBCO and NCCO), this allows us to estimate the value of U-ε_p for these materials, within this model. We compute the density of states for these and the effect of (U,ε_p) on the n_d-n_p curve, superconductivity, and antiferromagnetism.

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