Microscopic origin of diagonal stripe phases in doped nickelates

Abstract

We investigate the electron density distribution and the stability of stripe phases in the realistic two-band model with hopping elements between e_g orbitals at Ni sites on the square lattice, and compare these results with those obtained for the doubly degenerate Hubbard model with two equivalent orbitals and diagonal hopping. For both models we determine the stability regions of filled and half-filled stripe phases for increasing hole doping x=2-n in the range of x<0.4, using Hartree-Fock approximation for large clusters. In the parameter range relevant to the nickelates, we obtain the most stable diagonal stripe structures with filling of nearly one hole per atom, as observed experimentally. In contrast, for the doubly degenerate Hubbard model the most stable stripes are somewhat reminiscent of the cuprates, with half-filled atoms at the domain wall sites. This difference elucidates the crucial role of the off-diagonal e_g hopping terms for the stripe formation in La_2-xSr_xNiO_4. The influence of crystal field is discussed as well.

15 pages, 12 figures

References in corpus (1)

• Orbital liquid in ferromagnetic manganites: The orbital Hubbard model for $e_g$ electrons

Cited by in corpus (12)

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• Ground-state phase diagrams of the generalized Falicov-Kimball model with Hund coupling
• Charge Condensation and Lattice Coupling Drives Stripe Formation in Nickelates
• Spin and charge modulations of a half-filled extended Hubbard model
• Nanoscale inhomogeneity of charge density waves dynamics in La${}_{2-x}$Sr${}_x$NiO${}_4$
• Effect of the next-nearest neighbor hopping on the stability and band structure of the incommensurate phases in the cuprates
• Magnetic and orbital correlations in a two-site molecule
• Magnetic transitions in strong coupling expansions for nearly degenerate states
• Superconductivity in the spin-state crossover materials: Nickelates with planar-coordinated low-spin Ni${}^{2+}$ ions
• Phase coexistence in a half-filled extended Hubbard model
• Bad metal and negative compressibility transitions in a two-band Hubbard model