Model of charge triplets for high-T${}_c$ cuprates

Abstract

Starting with a minimal model for the CuO${}_2$ planes with the on-site Hilbert space reduced to a charge triplet of the three effective valence centers [CuO${}_4$]${}^{7-,6-,5-}$ (nominally Cu${}^{1+,2+,3+}$) with different conventional spin, different orbital symmetry, and different local lattice configuration, we develop a unified non-BCS spin-pseudospin model to describe the main phase states of doped cuprates. We argue that antiferromagnetic insulating, charge ordered, superconducting, and Fermi-liquid phases are possible phase states of a model parent cuprate, while typical phase state of a doped cuprate, in particular mysterious pseudogap phase, is a result of a phase separation. Superconductivity of cuprates is not a consequence of pairing of doped holes, but the result of quantum transport of on-site composite hole bosons, whereas main peculiarities of normal state can be related to an electron-hole interplay for unusual Fermi-liquid phase and features of the phase separation. Puzzlingly, but it is the electron-lattice interaction, which in the BCS model determines $s$-wave pairing, in the model of local composite bosons gives $d_{x^2-y^2}$-symmetry of the superconducting order parameter, thus showing once again a substantial involvement of the lattice in the cuprate's HTSC.

21 pages, oral presentation at the European Conference "Physics of Magnetism 2021"

References in corpus (7)

• Understanding electron-doped cuprate superconductors as hole superconductors
• Coexisting Holes and Electrons in High-Tc Materials: Implications from Normal State Transport
• Topological structures in unconventional scenario for 2D cuprates
• Phase diagrams of a 2D Ising spin-pseudospin model
• Critical temperatures of a model cuprate
• Specific Features of Phase States of a Diluted 2D Magnet with Frustration
• Pseudospin S=1 description of the cuprate complexity: the charge triplets model

Cited by in corpus (4)

• Pseudo-transition between antiferromagnetic and charge orders in a minimal spin-pseudospin model of one-dimensional cuprates
• Pseudotransitions in a dilute Ising chain
• Insulator-bad metal transition in RNiO${}_3$ nickelates beyond Hubbard model and density functional theory
• Predicting parameters of a model cuprate superconductor using machine learning