Influence of Local Correlations on the "Homogeneous Insulator-Superconductor" Transition in the Domain Boundaries of the Charge-Order Phase of a 2D System of a Mixed Valence

TL;DR

This study explores how local correlations influence the transition from an insulator to a superconductor at domain boundaries in a charge-ordered phase of a 2D mixed-valence system, revealing that small changes in on-site correlation U can induce significant structural and electronic transitions.

Contribution

It demonstrates through modeling that variations in on-site correlation U significantly alter the structure and electronic properties of domain boundaries in a 2D charge-ordered system, linking local correlations to phase transitions.

Findings

Boundary structure changes from nonconducting to superconducting with U variation

Small U variations induce significant structural and electronic transitions

Modeling shows correlation effects are crucial in phase behavior

Abstract

It is demonstrated in the (pseudo)spin S=1 formalism that the structure of antiphase domain boundaries in the phase of charge ordering of a mixed-valence system of the Cu1+, 2+, 3+ "triplet" type in cuprates on a two-dimensional square lattice depends to a considerable extent on on-site correlation parameter U. The results of computer modeling on large square lattices illustrate the change in the boundary structure (from a homogeneous monovalent nonconducting structure of the Cu2+ type to a filamentary superconducting one) induced by a relatively small variation of positive U values.