Magnetic structure of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">V</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>in the insulating phase

Castellani, C.; Natoli, C. R.; Ranninger, J.

doi:10.1103/physrevb.18.4945

Cited by 353 publications

(331 citation statements)

References 23 publications

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“…Moreover, the extensively investigated V 2 O 3 compound contains nominally two electrons in a doubly degenerate e g band and its phase diagram displays a paramagnetic MIT line which is first order [11]. Nevertheless, Castellani et al [18] have argued that a relevant model for this system should contain just one electron in a doubly degenerate e g band. In either case the qualitative physics is being correctly predicted by our results.…”

Section: Back Tomentioning

confidence: 99%

Integer-filling metal-insulator transitions in the degenerate Hubbard model

1997

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We obtain exact numerical solutions of the degenerate Hubbard model in the limit of large dimensions (or large lattice connectivity). Successive Mott-Hubbard metal insulator transitions at integer fillings occur at intermediate values of the interaction and low enough temperature in the paramagnetic phase. The results are relevant for transition metal oxides with partially filled narrow degenerate bands. 71.27.+a, 71.30.+h, 71.20.Ad The understanding of strongly correlated electron systems is one of the current challenges in condensed matter physics. In recent years, this problem has received a great deal of attention from theorists and experimentalist alike. Yet, our knowledge of even some of the basic features of the proposed model Hamiltonians remains to a large extent only partial, except, perhaps, in the onedimensional case. In consequence, the interpretation of the experimental data of strongly correlated electron systems has to remain only speculative in most of the cases. In regard of this situation, exact results on properties of model Hamiltonians in well defined limits is very desirable. The relevant role played by the band degeneracy in models of strongly correlated electrons has been long and largely recognized [1][2][3][4]. However, the systematic treatment of such models poses in general even greater technical difficulties than non-degenerate ones. This particularly applies to numerical approaches which have to deal with the exponential grow of the Hilbert space.The goal of this paper is to demonstrate the existence of successive metal insulator transitions (MIT) at the integer fillings n = 1, 2, 3 in the two band degenerate Hubbard model within the "Local impurity self-consistent approximation" (LISA) [5] which is exact in the limit of large dimensions (or large lattice connectivity) [6]. These MIT occur within the paramagnetic phase for intermediate values of the interaction. We obtain exact numerical solutions of the model using an extension of the Hirsch and Fye quantum Monte Carlo (HFQMC) algorithm [7,8] for the solution of the associated impurity problem within the LISA. This impurity problem is a generalized single impurity Anderson model where the impurity and conduction band operators carry an orbital index.The two band degenerate Hubbard model reads,ij labels nearest neighbor sites and a, b = 1, 2 is the orbital index. This Hamiltonian is rotational invariant in spin and real space and the usual approximation U and J independent of band indices is assumed [9]. The parameter U is due to on-site Coulomb repulsion and the exchange parameter J originates the Hund's coupling. For simplicity, we shall further assume t ab ij = −tδ ab and neglect the last "spin flip" term in (1). The resulting model Hamiltonian is relevant for for electronic systems with partially filled narrow degenerate bands. Examples of such systems are the 3d transition metal oxides R 1−x A x M O 3 with three-dimensional perovskitetype structure, where R = La, Y , A = Ca, Sr and the transition metal M = T i, V, Cr. Fujim...

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Section: Back Tomentioning

confidence: 99%

Integer-filling metal-insulator transitions in the degenerate Hubbard model

1997

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“…The following parametrization of UЈ and UЉ has been proven to be reliable 66,67 in the case of t 2g -based systems, UЈ = U −2J and UЉ = U −3J. No explicit double-counting term ⌺ dc was introduced in our specific calculations.…”

Section: ͑26͒mentioning

confidence: 99%

Dynamical mean-field theory using Wannier functions: A flexible route to electronic structure calculations of strongly correlated materials

et al. 2006

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A versatile method for combining density functional theory in the local density approximation with dynamical mean-field theory ͑DMFT͒ is presented. Starting from a general basis-independent formulation, we use Wannier functions as an interface between the two theories. These functions are used for the physical purpose of identifying the correlated orbitals in a specific material, and also for the more technical purpose of interfacing DMFT with different kinds of band-structure methods ͑with three different techniques being used in the present work͒. We explore and compare two distinct Wannier schemes, namely the maximally localized Wannier function and the Nth order muffin-tin-orbital methods. Two correlated materials with different degrees of structural and electronic complexity, SrVO 3 and BaVS 3 , are investigated as case studies. SrVO 3 belongs to the canonical class of correlated transition-metal oxides, and is chosen here as a test case in view of its simple structure and physical properties. In contrast, the sulfide BaVS 3 is known for its rich and complex physics, associated with strong correlation effects and low-dimensional characteristics. Insights into the physics associated with the metal-insulator transition of this compound are provided, particularly regarding correlationinduced modifications of its Fermi surface. Additionally, the necessary formalism for implementing selfconsistency over the electronic charge density in a Wannier basis is discussed.

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“…Vanadium oxide has three t 2g orbitals per V atom which are filled with two electrons. Two electrons (one per V ) are engaged in a strong cation-cation bond, leaving the remaining two in a twofold degenerate e g band 30 . LDA calculations give a bandwidth of ∼ 0.5eV 31 .…”

Section: A Hubbard Modelmentioning

confidence: 99%

“…LDA calculations give a bandwidth of ∼ 0.5eV 31 . The Hubbard model ignores the degeneracy of the band which is crucial in understanding the magnetic structure 30 , but captures the interplay of the electron-electron interactions and the kinetic energy. This delicate interplay of itinerancy and localization is responsible for many of the anomalous properties of this compound, and it is correctly predicted by this simplified model.…”

Section: A Hubbard Modelmentioning

confidence: 99%

Transfer of spectral weight in spectroscopies of correlated electron systems

1996

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We study the transfer of spectral weight in the photoemission and optical spectra of strongly correlated electron systems. Within the LISA, that becomes exact in the limit of large lattice coordination, we consider and compare two models of correlated electrons, the Hubbard model and the periodic Anderson model. The results are discussed in regard of recent experiments. In the Hubbard model, we predict an anomalous enhancement optical spectral weight as a function of temperature in the correlated metallic state which is in qualitative agreement with optical measurements in V2O3. We argue that anomalies observed in the spectroscopy of the metal are connected to the proximity to a crossover region in the phase diagram of the model. In the insulating phase, we obtain an excellent agreement with the experimental data and present a detailed discussion on the role of magnetic frustration by studying the k−resolved single particle spectra. The results for the periodic Anderson model are discussed in connection to recent experimental data of the Kondo insulators Ce3Bi4P t3 and F eSi. The model can successfully explain the different energy scales that are associated to the thermal filling of the optical gap, which we also relate to corresponding changes in the density of states. The temperature dependence of the optical sum rule is obtained and its relevance for the interpretation of the experimental data discussed. Finally, we argue that the large scattering rate measured in Kondo insulators cannot be described by the periodic Anderson model.

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Magnetic structure ofV2O3in the insulating phase

Cited by 353 publications

References 23 publications

Integer-filling metal-insulator transitions in the degenerate Hubbard model

Integer-filling metal-insulator transitions in the degenerate Hubbard model

Dynamical mean-field theory using Wannier functions: A flexible route to electronic structure calculations of strongly correlated materials

Transfer of spectral weight in spectroscopies of correlated electron systems

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