Frequency-dependent screened interaction in Ni within the random-phase approximation

Springer, Mitchell G.; Aryasetiawan, Ferdi

doi:10.1103/physrevb.57.4364

Cited by 118 publications

(101 citation statements)

References 14 publications

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“…We chose the value of U(ω = 0) (≃ 3.2eV ) by calculating the correlation function χ and ensuring that Eq. (11) is fulfilled at ω = 0, given the GW value for W loc (ω = 0) (≃ 2.2eV for Nickel [19]). This procedure emphasizes the low-frequency, screened value, of the effective interaction.…”

Section: Gwmentioning

confidence: 99%

First-Principles Approach to the Electronic Structure of Strongly Correlated Systems: Combining theGWApproximation and Dynamical Mean-Field Theory

Aryasetiawan²,

2003

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We propose a dynamical mean field approach for calculating the electronic structure of strongly correlated materials from first principles. The scheme combines the GW method with dynamical mean field theory, which enables one to treat strong interaction effects. It avoids the conceptual problems inherent to conventional "LDA+DMFT", such as Hubbard interaction parameters and double counting terms. We apply a simplified version of the approach to the electronic structure of nickel and find encouraging results.For systems with moderate Coulomb correlations the GW method (and its refinements) [1,2,3] is the tool of choice for the determination of excited states properties from first principles. It is a Green's function-based method, in which the effective screened interaction is treated at the RPA level, and used to construct an approximation to the electronic self-energy. This approach cures many of the artifacts encountered when the KohnSham orbitals are interpreted as physical excited states, while they are actually auxiliary quantities within Density Functional Theory (DFT).Although the GW approximation (GWA) has provided successful treatments of weakly to moderately correlated systems such as sp metals and semiconductors, applications to more strongly correlated systems with localized orbitals indicate a need to go beyond the GWA. For example, in ferromagnetic nickel, it was found [4] that the GWA is successful at predicting the quasiparticle bandnarrowing, but does not improve the (too large) exchange splitting found in DFT calculations in the local density approximation (LDA). The GWA also fails to reproduce the 6eV satellite observed in photoemission [21].Recently, a new approach to electronic structure calculations of strongly correlated materials involving d− or f − orbitals, has been developed. This approach, dubbed "LDA+DMFT", combines the dynamical mean-field theory (DMFT) [5] of correlated electron models with DFT-LDA calculations [6]. It is also a Green's function technique, but -unlike GWA -it does not treat the Coulomb interaction from first principles. Instead, an effective Hamiltonian involving Hubbard-like interaction parameters in the restricted subset of correlated orbitals is used as a starting point. It is thus necessary to introduce a "double-counting" correction term. The strength of DMFT however is that the onsite electronic interactions are treated to all orders, by using a mapping onto a selfconsistent quantum impurity problem. DMFT has led to remarkable advances on electronic structure calculations of materials in which the Mott phenomenon or the formation of local moments play a key role. This is the case, e.g. for the satellite structure in Ni, which has recently been shown to be correctly described by LDA+DMFT [7].The aim of this letter is to take a new step towards a first-principles electronic structure calculation method for strongly correlated materials. We propose a scheme in which the GW treatment of the screened Coulomb interaction and exchange self-energy is combined with a D...

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Section: Gwmentioning

confidence: 99%

First-Principles Approach to the Electronic Structure of Strongly Correlated Systems: Combining theGWApproximation and Dynamical Mean-Field Theory

Aryasetiawan²,

2003

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“…The determination of U from first principles has attracted growing interest in recent years. 67,74,[84][85][86][87][88][89][90][91][92] The most widely used approach is the constrained DFT formalism, which was developed in a general form by Dederichs et al 86 and later widely used to calculate parameters for effective Hamiltonians ͑Hubbard or Anderson͒. 93…”

Section: A Determination Of Umentioning

confidence: 99%

First-principles modeling of localizeddstates with theGW@LDA+Uapproach

et al. 2010

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First-principles modeling of systems with localized d states is currently a great challenge in condensedmatter physics. Density-functional theory in the standard local-density approximation ͑LDA͒ proves to be problematic. This can be partly overcome by including local Hubbard U corrections ͑LDA+ U͒ but itinerant states are still treated on the LDA level. Many-body perturbation theory in the GW approach offers both a quasiparticle perspective ͑appropriate for itinerant states͒ and an exact treatment of exchange ͑appropriate for localized states͒, and is therefore promising for these systems. LDA+ U has previously been viewed as an approximate GW scheme. We present here a derivation that is simpler and more general, starting from the static Coulomb-hole and screened exchange approximation to the GW self-energy. Following our previous work for f-electron systems ͓H. Jiang, R. I. Gomez-Abal, P. Rinke, and M. Scheffler, Phys. Rev. Lett. 102, 126403 ͑2009͔͒ we conduct a systematic investigation of the GW method based on LDA+ U͑GW @LDA+U͒, as implemented in our recently developed all-electron GW code FHI-gap ͑Green's function with augmented plane waves͒ for a series of prototypical d-electron systems: ͑1͒ ScN with empty d states, ͑2͒ ZnS with semicore d states, and ͑3͒ late transition-metal oxides ͑MnO, FeO, CoO, and NiO͒ with partially occupied d states. We show that for ZnS and ScN, the GW band gaps only weakly depend on U but for the other transition-metal oxides the dependence on U is as strong as in LDA+ U. These different trends can be understood in terms of changes in the hybridization and screening. Our work demonstrates that GW @LDA+U with "physical" values of U provides a balanced and accurate description of both localized and itinerant states.

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“…Indeed, the screened effective interaction W (r, r ′ ; ω) as estimated e.g from the RPA approximation, is a strong function of frequency (see e.g Ref. [5,6] for an ab-initio GW treatment in the case of Nickel). As a result, using an energy-independent parametrization of the on-site matrix elements of the Coulomb interaction such as (2) can only be appropriate for a description restricted to low-enough energies [6].…”

Section: Coulomb Repulsion and The Hubbard Umentioning

confidence: 99%

“…Summing (21) over k in order to obtain the onsite component G ii of the the lattice Green's function, and using (20), we arrive at the self-consistency condition 5 :…”

Section: The Mean-field Concept From Classical To Quantummentioning

confidence: 99%

“…At high energies (say, above the plasma frequency in a metal), it has a very large value associated with the bare, unscreened, matrix element, while at low energy screening takes place and it is considerably reduced. For first-principle RPA studies of the frequency dependence of the screened local interaction, see [5,6].…”

Section: A Life Without U: Towards Ab-initio Dmftmentioning

confidence: 99%

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Strongly Correlated Electron Materials: Dynamical Mean-Field Theory and Electronic Structure

Georges¹

2004

AIP Conference Proceedings

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Abstract. These are introductory lectures to some aspects of the physics of strongly correlated electron systems. I first explain the main reasons for strong correlations in several classes of materials. The basic principles of dynamical mean-field theory (DMFT) are then briefly reviewed. I emphasize the formal analogies with classical mean-field theory and density functional theory, through the construction of free-energy functionals of a local observable. I review the application of DMFT to the Mott transition, and compare to recent spectroscopy and transport experiments. The key role of the quasiparticle coherence scale, and of transfers of spectral weight between low-and intermediate or high energies is emphasized. Above this scale, correlated metals enter an incoherent regime with unusual transport properties. The recent combinations of DMFT with electronic structure methods are also discussed, and illustrated by some applications to transition metal oxides and f-electron materials.

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Frequency-dependent screened interaction in Ni within the random-phase approximation

Cited by 118 publications

References 14 publications

First-Principles Approach to the Electronic Structure of Strongly Correlated Systems: Combining theGWApproximation and Dynamical Mean-Field Theory

First-Principles Approach to the Electronic Structure of Strongly Correlated Systems: Combining theGWApproximation and Dynamical Mean-Field Theory

First-principles modeling of localizeddstates with theGW@LDA+Uapproach

Strongly Correlated Electron Materials: Dynamical Mean-Field Theory and Electronic Structure

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