Ferro-Orbitally Ordered Stripes in Systems with Alternating Orbital Order

Wróbel, P.; Oleś, Andrzej M.

doi:10.1103/physrevlett.104.206401

Cited by 35 publications

(40 citation statements)

References 26 publications

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“…A key role in their occurrence is played on one side by the frustrated localized-itinerant nature of the magnetic correlations, and on the other side by the peculiar orbital dependent electron dynamics in partially filled e g and t 2g sectors of d shells. Prototype examples of electronic self-organization are provided by the magnetic and charge orders detected in layered manganites [5-7] and nickelates [8].The formation of spin-charge density modulations is strongly related to the orbital character of the electronic system as demonstrated by the dominant role of lattice distortions in itinerant e g systems [9-11] compared with the spin-orbital exchanges in models of insulating t 2g electrons [12,13]. More unexplored is the case of partially localized t 2g electrons in systems with low dimensionality and competing magnetic correlations.…”

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confidence: 99%

Zigzag and Checkerboard Magnetic Patterns in Orbitally Directional Double-Exchange Systems

et al. 2015

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We analyze a t(2g) double-exchange system where the orbital directionality of the itinerant degrees of freedom is a key dynamical feature that self-adjusts in response to doping and leads to a phase diagram dominated by two classes of ground states with zigzag and checkerboard patterns. The prevalence of distinct orderings is tied to the formation of orbital molecules that in one-dimensional paths make insulating zigzag states kinetically more favorable than metallic stripes, thus allowing for a novel doping-induced metal-to-insulator transition. We find that the basic mechanism that controls the magnetic competition is the breaking of orbital directionality through structural distortions, and highlight the consequences of the interorbital Coulomb interaction.

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confidence: 99%

Zigzag and Checkerboard Magnetic Patterns in Orbitally Directional Double-Exchange Systems

et al. 2015

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“…Recent progress in understanding transition metal oxides with orbital degrees of freedom demonstrated many unusual properties of systems with active t 2g degrees of freedom -they are characterized by anisotropic hopping [4][5][6][7][8] which generates Ising-like orbital interactions [9][10][11][12][13][14][15][16][17], similar to the orbital superexchange in e g systems [18,19]. Particularly challenging are 4d and 5d transition metal oxides, where the interplay between strong electron correlations and spin-orbit interaction leads to several novel phases [20,21].…”

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confidence: 99%

Phase diagram and spin correlations of the Kitaev-Heisenberg model: Importance of quantum effects

et al. 2017

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We explore the phase diagram of the Kitaev-Heisenberg model with nearest neighbor interactions on the honeycomb lattice using the exact diagonalization of finite systems combined with the cluster mean field approximation, and supplemented by the insights from the linear spin-wave and second-order perturbation theories. This study confirms that by varying the balance between the Heisenberg and Kitaev term, frustrated exchange interactions stabilize in this model four phases with magnetic long range order: Néel phase, ferromagnetic phase, and two other phases with coexisting antiferromagnetic and ferromagnetic bonds, zigzag and stripy phases. They are separated by two disordered quantum spin-liquid phases, and the one with ferromagnetic Kitaev interactions has a substantially broader range of stability as the neighboring competing ordered phases, ferromagnetic and stripy, have very weak quantum fluctuations. Focusing on the quantum spin-liquid phases, we study spatial spin correlations and dynamic spin structure factor of the model by the exact diagonalization technique, and discuss the evolution of gapped low-energy spin response across the quantum phase transitions between the disordered spin liquid and magnetic phases with long range order.

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“…9 We predict that the optical conductivity would have this form in weakly doped Mott insulators with active orbital degrees of freedom, while at higher doping orbital stripes would form. 40 Similarly to the spin dynamics of stripes in superconducting cuprates, 41 one expects qualitative changes in the optical conductivity for systems with domains of AO order separated by orbital stripes, which is an interesting topic for future studies. Other challenges are posed by orbital superfluidity in the p band of a bipartite optical square lattice investigated recently 42 or by spin-orbital systems, where an orbiton may separate from a spinon and propagate through a lattice as a distinct quasiparticle.…”

Section: Discussionmentioning

confidence: 99%

Optical conductivity due to orbital polarons in systems with orbital degeneracy

Wróbel¹,

Eder²,

Oleś³

2012

Phys. Rev. B

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We consider the impact of orbital polarons in doped orbitally ordered systems on optical conductivity using the simplest generic model capturing the directional nature of either t 2g (or e g ) orbital states in certain transition metal oxides or p orbital states of cold atoms in optical lattices. The origin of the optical transitions is analyzed in detail and we demonstrate that the optical spectra (i) are determined by the string picture, i.e., flipped orbitals along the hole hopping path, and (ii) consist of three narrow peaks which stem from distinct excitations. They occur within the Mott-Hubbard gap similar to the superconducting cuprates but indicate hole confinement, in contrast to the spin t-J model. Finally, we point out how to use the point group symmetry to classify the optical transitions.

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Ferro-Orbitally Ordered Stripes in Systems with Alternating Orbital Order

Cited by 35 publications

References 26 publications

Zigzag and Checkerboard Magnetic Patterns in Orbitally Directional Double-Exchange Systems

Zigzag and Checkerboard Magnetic Patterns in Orbitally Directional Double-Exchange Systems

Phase diagram and spin correlations of the Kitaev-Heisenberg model: Importance of quantum effects

Optical conductivity due to orbital polarons in systems with orbital degeneracy

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