Nonresonant Raman response of inhomogeneous structures in the electron-dopedt‐t′Hubbard model

Abstract

We calculate the nonresonant Raman response, the single particle spectra and the charge-spin configuration for the electron-doped t-tЈ 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 component even when no Fermi surface is found in the nodal direction.

Nature of the inhomogeneous state of the extended t-J model on a square lattice

“…Within an unrestricted Hartree-Fock approach, the occurrence of the diagonal filled stripes having average of one doped electron per stripe site has been demonstrated earlier 24 . Later, the vertical "in-phase" stripe domains without π-phase-shifted staggered magnetic moment in the t − t ′ Hubbard model have been found in the electron-doped regime 25 . The unusual doping evolution of the Fermi surface detected by angle-resolved photoemission spectroscopy 26 was explained by assuming the inhomogeneous in-phase stripe phases 27 but without including strong correlations.…”

Inhomogeneous state of the extendedt-Jmodel on a square lattice: A variational Monte Carlo and Gutzwiller approximation study

“…24 Later, the vertical "in-phase" stripe domains without πphase-shifted staggered magnetic moment in the t-t Hubbard model have been found in the electron-doped regime. 25 The unusual doping evolution of the Fermi surface detected by angle-resolved photoemission spectroscopy 26 was explained by assuming the inhomogeneous in-phase stripe phases 27 but without including strong correlations. Since the strong correlation makes the difference in energies between uniform states and various hole-doped stripe states very small which has been shown recently, 11,28 it is beyond the accuracy of Hartree-Fock method to address this kind of difference.…”