Doping-driven Mott transition in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi mathvariant="normal">La</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">Sr</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:mi mathvariant="normal">Ti</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>via simultaneous electron and hole dopin

Liebsch, A.

doi:10.1103/physrevb.77.115115

Cited by 15 publications

(8 citation statements)

References 41 publications

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“…On the other hand, to compensate the polarization charges at the head-to-head domain wall, two electrons on two Ti atoms were localized at the domain wall by adding an on-site Coulomb repulsion term (characterized by a Hubbard parameter U ) on the d states of all Ti atoms in the film. Here, the simulation is guided by the studies of other Ti 3+ systems, e.g., LaTiO 3 , where an orbital polarization and accompanying gap opening is observed for a value of U between 5 and 6 eV [25]. Other DFT+U studies of single, localized Ti d electrons, e.g., at polar/nonpolar interfaces applied U values ranging from 4 eV [26] to 8 eV [27].…”

Section: B C(2×2) Unit Cellsmentioning

confidence: 99%

Charge and orbital order at head-to-head domain walls inPbTiO3

et al. 2014

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At ferroelectric longitudinal domain walls there is an uncompensated charge, which could form a twodimensional electron gas in the insulator. However, the uncompensated charges can be accommodated by, e.g., defects or localized states that split off from the conduction band. We carried out density functional theory calculations to study these scenarios in PbTiO 3 with and without consideration of strong correlation effects simulated via inclusion of a Hubbard parameter U. The optimized structure and electronic structure depend on the choice of this parameter: For vanishing U , a broad, conducting domain wall is obtained, while increasing U leads to localized Ti 3d states and an insulating, sharp domain wall. We also investigated the effects of varying the ferroelectric polarization on the electronic structure of these domain walls.

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Section: B C(2×2) Unit Cellsmentioning

confidence: 99%

Charge and orbital order at head-to-head domain walls inPbTiO3

et al. 2014

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“…ED DMFT cluster spectra illustrating the doping dependence in LaTiO 3 , and cluster spectra corresponding to the orthorhombic and tetragonal bulk phases, can be found in Refs. [66] and [63], respectively.…”

Section: Latiomentioning

confidence: 99%

Temperature and bath size in exact diagonalization dynamical mean field theory

Liebsch

Ishida

2011

J. Phys.: Condens. Matter

108

133

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Dynamical mean field theory (DMFT), combined with finite-temperature exact diagonalization, is one of the methods used to describe electronic properties of strongly correlated materials. Because of the rapid growth of the Hilbert space, the size of the finite bath used to represent the infinite lattice is severely limited. In view of the increasing interest in the effect of multi-orbital and multi-site Coulomb correlations in transition metal oxides, high-T(c) cuprates, iron-based pnictides, organic crystals, etc, it is appropriate to explore the range of temperatures and bath sizes in which exact diagonalization provides accurate results for various system properties. On the one hand, the bath must be large enough to achieve a sufficiently dense level spacing, so that useful spectral information can be derived, especially close to the Fermi level. On the other hand, for an adequate projection of the lattice Green's function onto a finite bath, the choice of the temperature is crucial. The role of these two key ingredients in exact diagonalization DMFT is discussed for a wide variety of systems in order to establish the domain of applicability of this approach. Three criteria are used to illustrate the accuracy of the results: (i) the convergence of the self-energy with the bath size, (ii) the quality of the discretization of the bath Green's function, and (iii) comparisons with complementary results obtained via continuous-time quantum Monte Carlo DMFT. The materials comprise a variety of three-orbital and five-orbital systems, as well as single-band Hubbard models for two-dimensional triangular, square and honeycomb lattices, where non-local Coulomb correlations are important. The main conclusion from these examples is that a larger number of correlated orbitals or sites requires a smaller number of bath levels. Down to temperatures of 5-10 meV (for typical bandwidths W ≈ 2 eV) two bath levels per correlated impurity orbital or site are usually adequate.

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“…We predict that the filling-controlled transition is first order as a consequence, implying that phase separation occurs and the critical doping scales as x c ∼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi U − U c p , where U c defines the critical U for the bandwidth-controlled transition. Using the prototypical example of the rare-earth titanates, an experimentally [28,29] and theoretically [30][31][32] well-characterized family of Mott compounds, we show how to compute x c within electronic structure calculations [33].…”

Section: Introductionmentioning

confidence: 99%

Phase Separation in Doped Mott Insulators

Yee

2015

Phys. Rev. X

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Motivated by the commonplace observation of Mott insulators away from integer filling, we construct a simple thermodynamic argument for phase separation in first-order doping-driven Mott transitions. We show how to compute the critical dopings required to drive the Mott transition using electronic structure calculations for the titanate family of perovskites, finding good agreement with experiment. The theory predicts that the transition is percolative and should exhibit Coulomb frustration.

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Doping-driven Mott transition inLa1−xSrxTiO3via simultaneous electron and hole dopin

Cited by 15 publications

References 41 publications

Charge and orbital order at head-to-head domain walls inPbTiO3

Charge and orbital order at head-to-head domain walls inPbTiO3

Temperature and bath size in exact diagonalization dynamical mean field theory

Phase Separation in Doped Mott Insulators

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