Stripe phases - possible ground state of the high-Tc superconductors

TL;DR

This paper investigates the stability of stripe phases in high-temperature superconductors using mean-field methods on Hubbard models, revealing how small energy differences and perturbations influence phase transitions and stripe formation.

Contribution

It provides a detailed analysis of charge and magnetic stripe phases, including effects of lattice coupling and perturbations, advancing understanding of their possible ground states.

Findings

Small energy difference between site-centered and bond-centered stripes

Phase transitions induced by next nearest hopping and lattice anisotropy

Role of electron-lattice coupling in stripe stability

Abstract

Based on the mean-field method applied either to the extended single-band Hubbard model or to the single-band Peierls-Hubbard Hamiltonian we study the stability of both site-centered and bond-centered charge domain walls. The difference in energy between these phases is found to be small. Therefore, moderate perturbations to the pure Hubbard model, such as next nearest hopping, lattice anisotropy, or coupling to the lattice, induce phase transitions, shown in the corresponding phase diagrams. In addition, we determine for stable phases charge and magnetization densities, double occupancy, kinetic and magnetic energies, and investigate the role of a finite electron-lattice coupling. We also review experimental signatures of stripes in the superconducting copper oxides.