Electronic Structure of Stripes in Two-Dimensional Hubbard Model

TL;DR

This paper investigates the electronic structure of stripe phases in the two-dimensional Hubbard model relevant to cuprate superconductors, revealing how Fermi surface topology and incommensurability influence metallicity and spectral features.

Contribution

It introduces a realistic Fermi surface topology into the Hubbard model to analyze stripe structures, highlighting the transition from insulator to metal and solitonic features.

Findings

Fermi surface shape varies with incommensurability and hole density.

Stripe regions can be metallic depending on delta/n_h ratio.

Mid-gap states significantly affect spectral and optical properties.

Abstract

Focusing on La_{2-x}Sr_{x}CuO_{4}, we study the stripe structure by the self-consistent mean-field theory of the Hubbard model. By introducing the realistic Fermi surface topology, the SDW-gapped insulator is changed to metallic. The solitonic features of the stripe structure and the contribution of the mid-gap states are presented. We consider the band dispersion, the local density of states, the spectral weight, and the optical conductivity, associated with the solitonic structure. These results may provide important information for the experimental research of the stripe structure, such as the angle-resolved photoemission experiments. The ``Fermi surface'' shape is changed depending on the ratio of the incommensurability delta and the hole density n_h. In real space, only the stripe region is metallic when delta/n_h is large.