Fragmentation of bands and the Fermi surfaces in stripe phases

TL;DR

This study uses mean-field analysis of the t-t'-U Hubbard model to explore how stripe phases influence Fermi surface fragmentation and electronic properties, potentially explaining phenomena in high-temperature superconductors.

Contribution

It demonstrates the formation of impurity subbands localized on domain walls and links Fermi surface topology changes to stripe width and doping levels.

Findings

Impurity subbands form on domain walls in stripe phases.

Fermi surface segments relate to impurity bands or delocalized states.

Diagonal stripes can lead to dielectric states at nonzero doping.

Abstract

The mean-field study of the stripe phases of t-t'-U Hubbard model confirms formation of the "impurity" subbands of states localized on domain walls. For bond-aligned stripes it is shown that segments of the Fermi surfaces (FS) in antinodal and nodal directions correspond to the "impurity" band or to that delocalized over a whole antiferromagnet domain. This might explain the dichotomy between corresponding quasiparticles in La_{2-x}Sr_xCuO_4. The Fermi surface changes its topology at some doping depending on stripe width. Additional ordering at the domain walls should be supposed to accord the observed 1/8 anomaly and the stripe spacing. It is confirmed also that the diagonal stripes can provide the dielectric state at nonzero doping.