Multiorbital kinetic effects on charge ordering of frustrated electrons on the triangular lattice

Février, Clément; Fratini, Simone; Ralko, Arnaud

doi:10.1103/physrevb.91.245111

Cited by 7 publications

(5 citation statements)

References 49 publications

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“…Here, a large metallic phase, with honeycomb-like charge ordering, appears, for relatively small values of the intramolecular interaction. This charge-ordered pattern is similar to the three-sublattice one [46,50,51], which has been stabilized on the triangular lattice for intermediate values of the nearest-neighbor interaction. In our case, the periodicity is extended to 12 sites due to the anisotropy of the parameters.…”

Section: -Site Ordered Metallic Phasementioning

confidence: 56%

Charge orders in organic charge-transfer salts

et al. 2017

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Motivated by recent experimental suggestions of charge-order-driven ferroelectricity in organic charge-transfer salts, such as κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Cl, we investigate magnetic and charge-ordered phases that emerge in an extended twoorbital Hubbard model on the anisotropic triangular lattice at 3/4 filling. This model takes into account the presence of two organic BEDT-TTF molecules, which form a dimer on each site of the lattice, and includes short-range intramolecular and intermolecular interactions and hoppings. By using variational wave functions and quantum Monte Carlo techniques, we find two polar states with charge disproportionation inside the dimer, hinting to ferroelectricity. These charge-ordered insulating phases are stabilized in the strongly correlated limit and their actual charge pattern is determined by the relative strength of intradimer to interdimer couplings. Our results suggest that ferroelectricity is not driven by magnetism, since these polar phases can be stabilized also without antiferromagnetic order and provide a possible microscopic explanation of the experimental observations. In addition, a conventional dimer-Mott state (with uniform density and antiferromagnetic order) and a nonpolar charge-ordered state (with charge-rich and charge-poor dimers forming a checkerboard pattern) can be stabilized in the strong-coupling regime. Finally, when electron-electron interactions are weak, metallic states appear, with either uniform charge distribution or a peculiar 12-site periodicity that generates honeycomb-like charge order.

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Section: -Site Ordered Metallic Phasementioning

confidence: 56%

Charge orders in organic charge-transfer salts

et al. 2017

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“…An additional transition also appears within the pinball phase at large U and V , corresponding to the ordering of the mobile electrons on the honeycomb lattice (pinball charge order, PCO). These results will be discussed elsewhere [32].…”

Section: Phase Diagrammentioning

confidence: 67%

Pinball liquid phase from Hund's coupling in frustrated transition-metal oxides

Ralko

Merino²,

Fratini³

2015

Phys. Rev. B

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The interplay of nonlocal Coulomb repulsion and Hund's coupling in the d-orbital manifold in frustrated triangular lattices is analyzed by a multiband extended Hubbard model. We find a rich phase diagram with several competing phases, including a robust pinball liquid phase, which is an unconventional metal characterized by threefold charge order, bad metallic behavior, and the emergence of high-spin local moments. Our results naturally explain the anomalous charge-ordered metallic state observed in the triangular layered compound AgNiO 2 . The potential relevance to other triangular transition-metal oxides is discussed.

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“…This state is characterized by quasilocalized charges coexisting with more itinerant electrons, which gives rise to strong quasi-particles renormalization with a mechanism analogous to the heavy fermion compounds 49 . In the multi-orbital case 56 , which is relevant for transition-metal oxides, the onset of a pinball phase has been associated to the a finite value of the Hund's exchange 57 .…”

Section: Introductionmentioning

confidence: 99%

Doping-driven metal-insulator transitions and charge orderings in the extended Hubbard model

et al. 2017

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We perform a thorough study of an extended Hubbard model featuring local and nearest-neighbor Coulomb repulsion. Using dynamical mean-field theory we investigated the zero temperature phasediagram of this model as a function of the chemical doping. The interplay between local and non-local interaction drives a variety of phase-transitions connecting two distinct charge-ordered insulators, i.e., half-filled and quarter-filled, a charge-ordered metal and a Mott insulating phase. We characterize these transitions and the relative stability of the solutions and we show that the two interactions conspire to stabilize the quarter-filled charge ordered phase.

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Multiorbital kinetic effects on charge ordering of frustrated electrons on the triangular lattice

Cited by 7 publications

References 49 publications

Charge orders in organic charge-transfer salts

Charge orders in organic charge-transfer salts

Pinball liquid phase from Hund's coupling in frustrated transition-metal oxides

Doping-driven metal-insulator transitions and charge orderings in the extended Hubbard model

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