Magnetic Phase Diagram of a Five-Orbital Hubbard Model in the Real-Space Hartree Fock Approximation Varying the Electronic Density

Abstract

Using the real-space Hartree Fock approximation, the magnetic phase diagram of a five-orbital Hubbard model for the iron-based superconductors is studied varying the electronic density $n$ in the range from 5 to 7 electrons per transition metal atom. The Hubbard interaction $U$ is also varied, at a fixed Hund coupling $J/U=0.25$. Several qualitative trends and a variety of competing magnetic states are observed. At $n$=5, a robust G-type antiferromagnetic insulator is found, in agreement with experimental results for BaMn${}_2$As${}_2$. As $n$ increases away from 5, magnetic states with an increasing number of nearest-neighbors ferromagnetic links become energetically stable. This includes the well-known C-type antiferromagnetic state at $n$=6, the E-phase known to exist in FeTe, and also a variety of novel states not found yet experimentally, some of them involving blocks of ferromagnetically oriented spins. Regions of phase separation, as in Mn-oxides, have also been detected. Comparison with previous theoretical investigations indicate that these qualitative trends may be generic characteristics of phase diagrams of multiorbital Hubbard models.

9 pages, 6 figures and 3 tables

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• Magnetic properties and pairing tendencies of the iron-based superconducting ladder BaFe${}_2$S${}_3$: combined ab initio and density matrix renormalization group study
• Ab initio downfolding study of the iron-based ladder superconductor BaFe${}_2$S${}_3$
• Pairing Tendencies in a Two-orbital Hubbard Model in One Dimension
• Impact of local-moment fluctuations on the magnetic degeneracy of iron arsenide superconductors
• Bicollinear Antiferromagnetic Order, Monoclinic Distortion, and Reversed Resistivity Anisotropy in FeTe as a Result of Spin-Lattice Coupling
• Magnetic states of the five-orbital Hubbard model for one-dimensional iron-based superconductors
• Block orbital-selective Mott insulators: a spin excitation analysis
• Orbital-selective Mott phases of a one-dimensional three-orbital Hubbard model studied using computational techniques
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• Thermal evolution of antiferromagnetic correlations and tetrahedral bond angles in superconducting FeTe${}_{1-x}$Se${}_x$
• Noncollinear and noncoplanar magnetic order in the extended Hubbard model on anisotropic triangular lattice
• Quantum magnetism of iron-based ladders: Blocks, spirals, and spin flux
• Magnetic field effects in electron systems with imperfect nesting
• Competition of spatially inhomogeneous states in antiferromagnetic Hubbard model