The conductivity tensor for the Hubbard model

Mancini, Francesco Paolo; Villani, D.

doi:10.1016/s0375-9601(99)00616-7

Cited by 5 publications

(5 citation statements)

References 21 publications

(43 reference statements)

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“…We found the changes of current carrier type around n = 2/3, 1, 4/3. In the limiting case of the absence of correlated hopping our results for the static conductivity agree with the concentration dependences obtained in the composite operator method [3], exact diagonalization [5], and Monte Carlo simulation [6] results. In the magnetic field static conductivity reflects the changes of single electron energy spectrum through correlation narrowing of the band and shift of subband center.…”

Section: Discussionsupporting

confidence: 85%

“…Hubbard model [1] is the simplest model describing the essential physics of materials with strong electron correlations and is used intensively. Theoretical investigations of the conductivity in the Hubbard model last for many decades, by both analytical [2][3][4] and numerical [5,6] methods. Extensive investigations of ferromagnetic properties of the model have been done (see [7,8] and references therein).…”

Section: Introductionmentioning

confidence: 99%

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Mott Transition, Ferromagnetism and Conductivity in the Generalized Hubbard Model

et al. 2007

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The electron correlations in narrow energy bands are examined within the framework of the Hubbard model, generalized by taking into account the correlated hopping of electrons. Electronic conductivity and ferromagnetic ordering stabilization in the system with various forms of electronic density of states are studied. The influence of magnetic field, temperature and the form of density of states on concentration dependence of conductivity and magnetization is investigated. The correlated hopping is shown to cause the electron-hole asymmetry of transport and ferromagnetic properties of narrow band materials.

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Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Mott Transition, Ferromagnetism and Conductivity in the Generalized Hubbard Model

et al. 2007

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“…This procedure has allowed us to obtain analytical expression for the band narrowing factor and relatively simple and transparent equations for calculation of spin-dependent shift of the band center, magnetization, static conductivity and effective mass of the current carrier. The results of our study generalize the results of works [6,16], where the static conductivity of the Hubbard model has been calculated as a function of electron concentration n, for a wider class of systems, for which the correlated hopping should be taken into account. In the limiting case of the absence of correlated hopping our results agree with the concentrational dependencies obtained in the composite operator method [6], exact diagonalization [16] and Monte-Carlo simulations [18] results.…”

supporting

confidence: 85%

“…The results of our study generalize the results of works [6,16], where the static conductivity of the Hubbard model has been calculated as a function of electron concentration n, for a wider class of systems, for which the correlated hopping should be taken into account. In the limiting case of the absence of correlated hopping our results agree with the concentrational dependencies obtained in the composite operator method [6], exact diagonalization [16] and Monte-Carlo simulations [18] results. The temperature dependence of conductivity in paramagnetic state, calculated in this work, agrees with the corresponding results of DMFT [24,37].…”

supporting

confidence: 85%

“…Theoretical investigations of the optical conductivity in the Hubbard model [3] in the frameworks of the Kubo linear response theory [4] last for many decades, we note here the investigations by analytical methods: moment method [5], in composite operators method [6], in the mean-field theory [7,8], in the perturbative theory method [9,10] in the limit of weak interaction (|t| ≫ U), in method of the memory function [11,12], in the opposite limit (U ≫ |t|). The conductivity has been intensively studied in onedimensional Hubbard model [13]- [15], where the numerical results can be compared with exact ones obtained by Bethe ansatz application.…”

mentioning

confidence: 99%

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Magnetic field dependence of conductivity and effective mass of carriers in a model of Mott-Hubbard material

Didukh¹,

Kramar²,

Skorenkyy³

et al. 2005

Condens. Matter Phys.

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The effect of external magnetic field h on a static conductivity of Mott-Hubbard material which is described by the model with correlated hopping of electrons has been investigated. By means of canonical transformation, the effective Hamiltonian is obtained which takes into account strong intra-site Coulomb repulsion and correlated hopping. Using a variant of generalized Hartree-Fock approximation the single-electron Green function and quasiparticle energy spectrum of the model have been calculated. The static conductivity σ has been calculated as a function of h, electron concentration n and temperature T. The correlated hopping is shown to cause the electron-hole asymmetry of transport properties of narrow band materials

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The Hubbard model within the equations of motion approach

Mancini¹,

Avella²

2004

Advances in Physics

104

228

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The Hubbard model plays a special role in condensed matter theory as it is considered to be the simplest Hamiltonian model one can write in order to describe anomalous physical properties of some class of real materials. Unfortunately, this model is not exactly solved except in some limits and therefore one should resort to analytical methods, like the Equations of Motion Approach, or to numerical techniques in order to attain a description of its relevant features in the whole range of physical parameters (interaction, filling and temperature). In this paper, the Composite Operator Method, which exploits the above mentioned analytical technique, is presented and systematically applied in order to get information about the behaviour of all relevant properties of the model (local, thermodynamic, single-and two-particle properties) in comparison with many other analytical techniques, the above cited known limits and numerical simulations. Within this approach, the Hubbard model is also shown to be capable of describing some anomalous behaviour of cuprate superconductors.

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The conductivity tensor for the Hubbard model

Cited by 5 publications

References 21 publications

Mott Transition, Ferromagnetism and Conductivity in the Generalized Hubbard Model

Mott Transition, Ferromagnetism and Conductivity in the Generalized Hubbard Model

Magnetic field dependence of conductivity and effective mass of carriers in a model of Mott-Hubbard material

The Hubbard model within the equations of motion approach

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