Non-resonant Raman response of inhomogeneous structures in the electron doped $t-t'$ Hubbard model

TL;DR

This paper investigates the non-resonant Raman response and electronic structures of the electron-doped $t-t'$ Hubbard model, revealing inhomogeneous stripe phases and their impact on spectral features, contrasting with hole-doped cuprates.

Contribution

It provides a detailed analysis of inhomogeneous structures in the electron-doped Hubbard model using unrestricted Hartree-Fock, highlighting differences from hole doping and connecting to experimental observations.

Findings

Inhomogeneous stripe phases are energetically favorable at high $U$ and intermediate doping.

Inhomogeneities produce an incoherent background in the Raman response.

The $B_{2g}$ signal can exhibit quasiparticle-like features without a Fermi surface.

Abstract

We calculate the non-resonant Raman response, the single particle spectra and the charge-spin configuration for the electron doped $t-t'$ Hubbard model using unrestricted Hartree-Fock calculations. We discuss the similarities and differences in the response of homogeneous versus inhomogeneous structures. Metallic antiferromagnetism dominates in a large region of the $U-n$ phase diagram but at high values of the on-site interaction and for intermediate doping values, inhomogeneous configurations are found with lower energy. This result is in contrast with the case of hole doped cuprates where inhomogeneities are found already at very low doping. The inhomogeneities found are in-phase stripes compatible with inelastic neutron scattering experiments. They give an incoherent background in the Raman response. The $B_{2g}$ signal can show a quasiparticle-like component even when no Fermi surface is found in the nodal direction.