From local to nonlocal correlations: The Dual Boson perspective

Stepanov, E. A.; Huber, A.; Loon, Erik G. C. P. van; Lichtenstein, A. I.; Katsnelson, M. I.

doi:10.1103/physrevb.94.205110

Cited by 50 publications

(96 citation statements)

References 38 publications

(92 reference statements)

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“…7 of Ref. [52], which were obtained in an HS-V flavor, yield phase boundaries which are much lower than either DB or the GW +EDMFT results in Fig. 9 (which correspond to the HS-UV variant of the decoupling of the interaction).…”

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

“…[52], and discussed in detail at the end of this section. Yet, the dual-boson variants start out with a lower slope, indicating stronger ordering tendencies already for the lowest values of U , while all GW +EDMFT variants follow the slope of the "weak-coupling" GW boundary in the vicinity of U = 0.…”

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

“…The only additional outlier is the simplest DB type of approximation, the DB-GW variant, for which Ref. [52] showed that it is formally similar to an HS-V calculation. More recently, Ref.…”

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

“…[48,49]), and lightweight improvements on EDMFT, especially with realistic applications in mind, are desirable. Recent attempts to forgo the computation of four-leg vertices include the TRiply Irreducible Local EXpansion (TRILEX) method [50,51] and simplified dual-boson schemes such as DB+GW or DB+GW γ [52]. Whether they retain the above-mentioned conserving properties, however, is yet unclear.…”

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

“…9, we compare the phase diagram for model (1) obtained from various simplified variants [52] of the dual-boson scheme and compare it to GW c +EDMFT, GW +EDMFT, and the (self-consistent) GW approximation. We restrict this comparison to values of U below the Mott transition, for lack of available dual-boson results in the Mott-insulating phase.…”

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

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Influence of Fock exchange in combined many-body perturbation and dynamical mean field theory

et al. 2017

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In electronic systems with long-range Coulomb interaction, the nonlocal Fock-exchange term has a bandwidening effect. While this effect is included in combined many-body perturbation theory and dynamical mean field theory (DMFT) schemes, it is not taken into account in standard extended DMFT (EDMFT) calculations. Here, we include this instantaneous term in both approaches and investigate its effect on the phase diagram and dynamically screened interaction. We show that the largest deviations between previously presented EDMFT and GW +EDMFT results originate from the nonlocal Fock term, and that the quantitative differences are especially large in the strong-coupling limit. Furthermore, we show that the charge-ordering phase diagram obtained in GW +EDMFT methods for moderate interaction values is very similar to the one predicted by dual-boson methods that include the fermion-boson or four-point vertex. DOI: 10.1103/PhysRevB.95.245130 Dynamical mean field theory (DMFT) [1] self-consistently maps a correlated Hubbard lattice problem with local interactions onto an effective impurity problem consisting of a correlated orbital hybridized with a noninteracting fermionic bath. If the bath is integrated out, one obtains an impurity action with retarded hoppings. Extended dynamical mean field theory [2-10] (EDMFT) extends the DMFT idea to systems with long-range interactions. It does so by mapping a lattice problem with long-range interactions onto an effective impurity model with self-consistently determined fermionic and bosonic baths, or, in the action formulation, an impurity model with retarded hoppings and retarded interactions.While EDMFT captures dynamical screening effects and charge-order instabilities, it has been found to suffer from qualitative shortcomings in finite dimensions. For example, the charge susceptibility computed in EDMFT does not coincide with the derivative of the average charge with respect to a small applied field [11], nor does it obey local charge conservation rules [12] essential for an adequate description of collective modes such as plasmons.The EDMFT formalism has an even more basic deficiency: since it is based on a local approximation to the self-energy, it does not include even the first-order nonlocal interaction term, the Fock term. The combined GW +EDMFT [13][14][15] scheme corrects this by supplementing the local self-energy from EDMFT with the nonlocal part of the GW diagram, where G is the interacting Green's function and W the fully screened interaction. Indeed, the nonlocal Fock term [Gv] nonloc is included in the nonlocal [GW ] nonloc diagram. As described in more detail in Ref. [15] (see also the appendix of Ref.[16]), the GW +EDMFT method is formally obtained by constructing an energy functional of G and W , the Almbladh [17] functional , and by approximating as a sum of two terms, one containing all local diagrams (corresponding to EDMFT) and the other containing the simplest nonlocal correction (corresponding to the GW approximation [18]). This functional construct...

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Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

“…The only additional outlier is the simplest DB type of approximation, the DB-GW variant, for which Ref. [52] showed that it is formally similar to an HS-V calculation. More recently, Ref.…”

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexmentioning

confidence: 99%

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Influence of Fock exchange in combined many-body perturbation and dynamical mean field theory

et al. 2017

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Charge density wave ordering in NdNiO2: effects of multiorbital nonlocal correlations

Stepanov,

Vandelli,

Lichtenstein

et al. 2024

npj Comput Mater

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In this work, we investigate collective electronic fluctuations and, in particular, the possibility of the charge density wave ordering in an infinite-layer NdNiO2. We perform advanced many-body calculations for the ab-initio three-orbital model by taking into account local correlation effects, nonlocal charge and magnetic fluctuations, and the electron-phonon coupling. We find that in the considered material, electronic correlations are strongly orbital- and momentum-dependent. Notably, the charge density wave and magnetic instabilities originate from distinct orbitals. In particular, we show that the correlation effects lead to the momentum-dependent hybridization between different orbitals, resulting in the splitting and shifting of the flat part of the Ni-$${d}_{{z}^{2}}$$ d z 2 band. This strong renormalization of the electronic spectral function drives the charge density wave instability that is related to the intraband Ni-$${d}_{{z}^{2}}$$ d z 2 correlations. Instead, the magnetic instability stems from the Ni-$${d}_{{x}^{2}-{y}^{2}}$$ d x 2 − y 2 orbital, which remains half-filled through the redistribution of the electronic density between different bands even upon hole doping. Consequently, the strength of the magnetic fluctuations remains nearly unchanged for the considered doping levels. We argue that this renormalization is not inherent to the stoichiometric case but can be induced by hole doping.

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Quantum spin fluctuations and evolution of electronic structure in cuprates

et al. 2018

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Correlation effects in CuO 2 layers give rise to a complicated landscape of collective excitations in high-T c cuprates. Their description requires an accurate account for electronic fluctuations at a very broad energy range and remains a challenge for the theory. Particularly, there is no conventional explanation of the experimentally observed "resonant" antiferromagnetic mode, which is often considered to be a mediator of superconductivity. Here we model spin excitations of the hole-doped cuprates in the paramagnetic regime and show that this antiferromagnetic mode is associated with electronic transitions between anti-nodal X and Y points of the quasiparticle band that is pinned to the Fermi level. We observe that upon doping of 7-12% the electronic spectral weight redistribution leads to the formation of a very stable quasiparticle dispersion due to strong correlation effects. The reconstruction of the Fermi surface results in a flattening of the quasiparticle band at the vicinity of the nodal MΓ/2 point, accompanied by a high density of charge carriers. Collective excitations of electrons between the nodal MΓ/2 and XM/2 points form the additional magnetic holes state in magnetic spectrum, which protects the antiferromagnetic fluctuation. Further investigation of the evolution of spin fluctuations with the temperature and doping allowed us to observe the incipience of the antiferromagnetic ordering already in the paramagnetic regime above the transition temperature. Additionally, apart from the most intensive low-energy magnetic excitations, the magnetic spectrum reveals less intensive collective spin fluctuations that correspond to electronic processes between peaks of the single-particle spectral function. arXiv:1806.05216v2 [cond-mat.str-el]

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From local to nonlocal correlations: The Dual Boson perspective

Cited by 50 publications

References 38 publications

Influence of Fock exchange in combined many-body perturbation and dynamical mean field theory

Influence of Fock exchange in combined many-body perturbation and dynamical mean field theory

Charge density wave ordering in NdNiO2: effects of multiorbital nonlocal correlations

Quantum spin fluctuations and evolution of electronic structure in cuprates

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