Dynamical mean field theory for diatomic molecules and the exact double counting

Lee, Juho; Haule, Kristjan

doi:10.1103/physrevb.91.155144

Cited by 11 publications

(13 citation statements)

References 35 publications

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“…The quantum impurity problem was solved by the continuous time quantum Monte Carlo (CTQMC) method [30,31], using the Slater form of the Coulomb repulsion in its fully rotational invariant form. Double counting of the electronic interactions was treated exactly [32].…”

Section: Dft+dmft Calculationsmentioning

confidence: 99%

Correlation-driven metal-insulator transition in proximity to an iron-based superconductor

et al. 2017

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We report the direct spectroscopic observation of a metal to correlated-insulator transition in the family of iron-based superconducting materials. By means of optical spectroscopy we demonstrate that the excitation spectrum of NaFe 1−x Cu x As develops a large gap with increasing copper substitution. Dynamical mean-field theory calculations show a good agreement with the experimental data and suggest that the formation of the charge gap requires an intimate interplay of strong on-site electronic correlations and spin-exchange coupling, revealing the correlated Slater-insulator nature of the antiferromagnetic ground state. Our calculations further predict the high-temperature paramagnetic state of the same compound to be a highly incoherent correlated metal. We verify this prediction experimentally by showing that the doping-induced weakening of antiferromagnetic correlations enables a thermal crossover from an insulating to an incoherent metallic state. Redistribution of the optical spectral weight in this crossover uncovers the characteristic energy of Hund's-coupling and Mott-Hubbard electronic correlations essential for the electronic localization. Our results demonstrate that NaFe 1−x Cu x As continuously transitions from the typical itinerant phases of iron pnictides to a highly incoherent metal and ultimately a correlated insulator. Such an electronic state is expected to favor high-temperature superconductivity.

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Section: Dft+dmft Calculationsmentioning

confidence: 99%

Correlation-driven metal-insulator transition in proximity to an iron-based superconductor

et al. 2017

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“…A simpler scheme, derived from the GW+DMFT, is the recently proposed "screened exchange dynamical mean field theory" 74,76 , where the DFT exchange-correlation potential is eliminated and replaced by a screened exchange term. We also mention a recent attempt to transfer this concept to the LDA+DMFT scheme 77 . These considerations motivate the construction of effective low-energy Hamiltonians based on many-body perturbation theory for the H part, rather than on the Kohn-Sham Hamiltonian of the DFT.…”

Section: Introductionmentioning

confidence: 99%

Low-energy effective Hamiltonians for correlated electron systems beyond density functional theory

Hirayama

Miyake²,

Imada

et al. 2017

Phys. Rev. B

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We propose a refined scheme of deriving an effective low-energy Hamiltonian for materials with strong electronic Coulomb correlations beyond density functional theory (DFT). By tracing out the electronic states away from the target degrees of freedom in a controlled way by a perturbative scheme we construct an effective model for a restricted low-energy target space incorporating the effects of high-energy degrees of freedom in an effective manner. The resulting effective model can afterwards be solved by accurate many-body solvers. We improve this "multi-scale ab initio scheme for correlated electrons" (MACE) primarily in two directions: (1) Double counting of electronic correlations between the DFT and the low-energy solver is avoided by using the constrained GW scheme. (2) The frequency dependence of the interaction emerging from the partial trace summation is taken into account as a renormalization to the low-energy dispersion. The scheme is successfully tested on the example of SrVO3. Our work opens unexplored ways to understanding the electronic structure of strongly correlated systems beyond current DFT methods.

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“…Here we propose a new method of calculating the overlap between DMFT and a band-structure method in solids, and we explicitly evaluate this DC functional within LDA+DMFT. Some ideas presented here come from studying the toy model of correlations, namely the H 2 molecule, in which the exact double-counting was found for the DMFT method applied to the single H atom of H 2 molecule [13], where the screening is absent. The derivation of the double-counting in the presence of screening in solids will be addressed in this letter, and will be tested on several well studied correlated materials, such as transition metal oxides SrVO 3 , LaVO 3 , and most studied lanthanide metal, the elemental Cerium.…”

mentioning

confidence: 99%

Exact Double Counting in Combining the Dynamical Mean Field Theory and the Density Functional Theory

2015

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We propose a continuum representation of the Dynamical Mean Field Theory, in which we were able to derive an exact overlap between the Dynamical Mean Field Theory and band structure methods, such as the Density Functional Theory. The implementation of this exact double-counting shows improved agreement between theory and experiment in several correlated solids, such as the transition metal oxides and lanthanides. Previously introduced nominal double-counting is in much better agreement with the exact double-counting than most widely used fully localized limit formula.

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Dynamical mean field theory for diatomic molecules and the exact double counting

Cited by 11 publications

References 35 publications

Correlation-driven metal-insulator transition in proximity to an iron-based superconductor

Correlation-driven metal-insulator transition in proximity to an iron-based superconductor

Low-energy effective Hamiltonians for correlated electron systems beyond density functional theory

Exact Double Counting in Combining the Dynamical Mean Field Theory and the Density Functional Theory

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