Charge Stripes in the Two-Orbital Hubbard Model for Pnictides

TL;DR

This study uses numerical methods to explore charge stripe formation in a two-orbital Hubbard model for pnictides, revealing stable charge and spin stripe patterns upon doping, with implications for experimental observations.

Contribution

It demonstrates the emergence of charge stripes in the two-orbital Hubbard model for pnictides using real-space Hartree-Fock calculations, highlighting their stability across different doping regimes.

Findings

Charge stripes form perpendicular to spin stripes upon electron doping.

Charge striped states are stable when the undoped state has a Hubbard gap.

Results suggest relevance to electronic nematicity and spin incommensurability in experiments.

Abstract

The two-orbital Hubbard model for the pnictides is studied numerically using the real-space Hartree-Fock approximation on finite clusters. Upon electron doping, states with a nonuniform distribution of charge are stabilized. The observed patterns correspond to charge stripes oriented perpendicular to the direction of the spin stripes of the undoped magnetic ground state. While these charge striped states are robust when the undoped state has a Hubbard gap, their existence when the intermediate-coupling magnetic metallic state of pnictides is doped was also observed for particular model parameters. Results for hole doping and implications for recent experiments that reported electronic nematic states and spin incommensurability are also briefly discussed.