Spin-orbital model for fullerides
arXiv:2103.04960 · doi:10.1103/PhysRevB.103.235145
Abstract
The multiorbital Hubbard model in the strong coupling limit is analyzed for the effectively antiferromagnetic Hund's coupling relevant to fulleride superconductors with three orbitals per molecule. The localized spin-orbital model describes the thermodynamics of the half-filled (three-electron) state with total spin-1/2, composed of singlon and doublon placed on the two of three orbitals. The model is solved using the mean-field approximation and magnetic and electric ordered states are clarified through the temperature dependences of the order parameters. Combining the model with the band structure from {\it ab initio} calculation, we also semi-quantitavely analyze the realistic model and the corresponding physical quantities. In the A15-structure fulleride model, there is an antiferromagnetic ordered state, and subsequently the two orbital ordered state appears at lower temperatures. It is argued that the origin of these orbital orders is related to the point group symmetry. As for the fcc-fulleride model, the time-reversal broken orbital ordered state is identified. Whereas the spin degeneracy remains in our treatment for the geometrically frustrated lattice, it is expected to be lifted by some magnetic ordering or quantum fluctuations, but not by the spin-orbital coupling which is effectively zero for fullerides in the strong-coupling regime.
arXiv comment15 pages, 11 figures
References in corpus (25)
- Superconductivity in Fullerides
- An optically stimulated superconducting-like phase in K3C60 far above equilibrium Tc
- Strongly Correlated Superconductivity
- Electronic origin of magnetic and orbital ordering in insulating LaMnO_3
- Modeling the Unconventional Superconducting Properties of Expanded AC Fullerides
- Unified understanding of superconductivity and Mott transition in alkali-doped fullerides from first principles
- Non magnetic molecular Jahn-Teller Mott insulators
- Pressure tuning of light-induced superconductivity in K3C60
- Ab initio derivation of electronic low-energy models for C60 and aromatic compounds
- Electronic orders in multi-orbital Hubbard models with lifted orbital degeneracy
- Ab initio downfolding for electron-phonon coupled systems: constrained density-functional perturbation theory (cDFPT)
- Frustration and entanglement in the spin--orbital model on a triangular lattice: valence--bond and generalized liquid states
- Exotic s-wave superconductivity in alkali-doped fullerides
- Theory of the Metal-Paramagnetic Mott-Jahn-Teller Insulator Transition in A_4C_{60}
- Spontaneous orbital-selective Mott transitions and the Jahn-Teller metal of AC
- Surprises in the Orbital Magnetic Moment and g-Factor of the Dynamic Jahn-Teller Ion C_{60}^-
- Superconductivity in the two-band Hubbard model
- Coexistence of full-gap superconductivity and pseudogap in two-dimensional fullerides
- Long-range orders, spin- and orbital-freezing in the two-band Hubbard model
- Spontaneously orbital-selective superconductivity in a three-orbital Hubbard model
- Visualizing molecular orientational ordering and electronic structure in CsnC60 fulleride films
- Staggered ordered phases in the three-orbital Hubbard model
- Entropy and electronic orders of the three-orbital Hubbard model with antiferromagnetic Hund coupling
- Unconventional orbital ordering and emergent dimensional reduction in fulleride superconductors
- Superconductivity Emerging from Excitonic Mott insulator - Theory of Alkaline Doped Fullerene