Kuz’min, V.I.; Nikolaev, S.V.; Korshunov, M.M.; Ovchinnikov, S.G. One- and Two-Particle Correlation Functions in the Cluster Perturbation Theory for Cuprates. Materials2023, 16, 4640.
Kuz’min, V.I.; Nikolaev, S.V.; Korshunov, M.M.; Ovchinnikov, S.G. One- and Two-Particle Correlation Functions in the Cluster Perturbation Theory for Cuprates. Materials 2023, 16, 4640.
Kuz’min, V.I.; Nikolaev, S.V.; Korshunov, M.M.; Ovchinnikov, S.G. One- and Two-Particle Correlation Functions in the Cluster Perturbation Theory for Cuprates. Materials2023, 16, 4640.
Kuz’min, V.I.; Nikolaev, S.V.; Korshunov, M.M.; Ovchinnikov, S.G. One- and Two-Particle Correlation Functions in the Cluster Perturbation Theory for Cuprates. Materials 2023, 16, 4640.
Abstract
Physics of high-Tc superconducting cuprates is obscured by the effect of strong electronic correlations. One way to overcome the problem is to seek for an exact solution at least within the small cluster and expand it to the whole crystal. Such an approach is in the heart of the cluster perturbation theory (CPT). Here we develop CPT for the dynamic charge and spin susceptibilities (spin-CPT), within which the correlation effects are explicitly taken into account by the exact diagonalization. We apply spin-CPT to the effective two-band Hubbard model for the cuprates obtained from the three-band Emery model and calculate one- and two-particle correlation functions, namely, spectral function and spin and charge susceptibilities. Doping dependence of the spin susceptibility was studied within spin-CPT and CPT-RPA that is the CPT generalization of the random phase approximation (RPA). Both methods produce the low energy response at four incommensurate wave vectors in qualitative agreement to the results of the inelastic neutron scattering on overdoped cuprates.
Keywords
Strong electronic correlations; Cuprates; Hubbard model; Cluster perturbation theory
Subject
Physical Sciences, Condensed Matter Physics
Copyright:
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