Phase diagram of La2-xSrxCuO4 and stripes

TL;DR

This paper presents a model explaining the phase diagram and spin textures of La2-xSrxCuO4 without assuming stripe formation, emphasizing geometrical relations and hole ordering, supporting a negative-U center mechanism for high-Tc superconductivity.

Contribution

The model offers a new explanation for stripe textures and phase diagram features based on lattice geometry and hole ordering, without presuming stripe formation.

Findings

Calculated phase diagrams closely match experimental data.

Stripe textures result from geometrical and ordering effects, not stripe formation.

Supports negative-U center mechanism as the basis for high-Tc superconductivity.

Abstract

An elementary model of La2-xSrxCuO4 explaining the features of its superconducting phase diagram and the characteristics of spin textures without any assumption of stripe formation is proposed. The foundations of this model are the mechanism of negative-U center formation proposed earlier, the supposition of rigid localization of doped holes, and the concept of specific ordering of doped ions. It is shown that within the framework of the proposed model the features of stripe textures of La2-xSrxCuO4 reflect exclusively the geometrical relations existing in a square lattice and the competition between different types of doped hole ordering. The detailed agreement between the calculated and experimental phase diagrams is the decisive factor favoring the mechanism of high-Tc superconductivity in which superconducting pairing arises due to scattering processes with intermediate virtual bound states of negative-U centers.