Self-consistent ladder dynamical vertex approximation

Kaufmann, Josef; Eckhardt, Christian; Pickem, Matthias; Kitatani, Motoharu; Kauch, Anna; Held, Karsten

doi:10.1103/physrevb.103.035120

Cited by 28 publications

(20 citation statements)

References 132 publications

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“…[52] and evaluate the selfenergy Σ k and the (dual) spin-fermion vertex Γ kq . The dual formulation implies some more specific features addressed in the supplemental material [59], but the physical interpretation of Γ is consistent with the discussion above. We fix the lattice size to N = 16 × 16, the temperature is T = 0.15t.…”

supporting

confidence: 68%

“…Method and model --Diagrammatic extensions [24] of dynamical mean-field theory (DMFT) [58] have proven useful to study spin fluctuations in strongly correlated systems. To reduce bias [59] we employ the method of Ref. [52], corresponding to the parquet approximation [60] for dual fermions [50,51].…”

mentioning

confidence: 99%

“…We denote its local spin-fermion vertex as Γ loc (ν, ω). The leading vertex correction due to local spin exchange has the imaginary part [59,67],…”

mentioning

confidence: 99%

“…This is a precursor to the decoupling of Goldstone excitations from fermions in the antiferromagnet, known as Adler principle [55,56,[72][73][74][75]; in the extreme case ξ → ∞ it requires that the vertex vanishes at the ordering vector [73]. For larger dopings the suppression moves to incommensurate momenta [59]. At PG, the Adler principle does not apply for small doping because of the gap.…”

mentioning

confidence: 99%

“…To reveal its quantitative effect we analyze the contribution Σsp (k, q) of nonlocal spin fluctuations to the dual self-energy, it has a form similar to Eq. ( 1) [59]. First, we integrate Σ sp (k, ν = πT, q, ω = 0) with respect to q over a circle with radius r q , centered at Q.…”

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confidence: 99%

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Spin scattering turns complex at strong coupling: the key to pseudogap and Fermi arcs in the Hubbard model

Krien,

Worm,

Chalupa

et al. 2021

Preprint

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We analyze the pseudogap phenomenon of hole-doped cuprates via a Feynman-diagrammatic inspection of the Hubbard model. Our approach captures the pivotal interplay between Mott localization and Fermi surface topology beyond weak-coupling spin fluctuations, which open a spectral gap near hot spots. We show that strong coupling and particle-hole asymmetry give rise to another mechanism: the spin-fermion vertex develops a large imaginary part. While its real part always suppresses the electronic lifetime, the imaginary part has a twofold effect. For antinodal fermions a gap opening is boosted; conversely, around the node Fermi arcs are protected.

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supporting

confidence: 68%

mentioning

confidence: 99%

“…We denote its local spin-fermion vertex as Γ loc (ν, ω). The leading vertex correction due to local spin exchange has the imaginary part [59,67],…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Spin scattering turns complex at strong coupling: the key to pseudogap and Fermi arcs in the Hubbard model

Krien,

Worm,

Chalupa

et al. 2021

Preprint

Self Cite

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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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Recent Developments and Future Directions

Aryasetiawan

Nilsson

2022

Downfolding Methods in Many-Electron Theory

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In this last chapter, very recent promising developments beyond GW+EDMFT by taking into account nonlocal vertex corrections beyond the RPA are described. The first development is the dual fermion and boson approach in which DMFT is used as a starting point for a perturbation expansion of the nonlocal self-energy. This approach is very general and in its lowest similar to the GW+EDMFT scheme. The second development is the TRILEX approach based on the extension of the GW+EDMFT scheme to include higher-order correlation or vertex functions in the self-consistency condition. Like the GW+EDMFT scheme, this approach maintains the basic concept of DMFT in that local projected quantities are made self-consistent. In this way, nonlocal spin fluctuations missing in the GW+EDMFT scheme are incorporated. The third development is the dynamical vertex approximation method, which can be considered as a generalization of DMFT assuming the locality of the two-particle irreducible vertex. This chapter closes with a summary.

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Self-consistent ladder dynamical vertex approximation

Cited by 28 publications

References 132 publications

Spin scattering turns complex at strong coupling: the key to pseudogap and Fermi arcs in the Hubbard model

Spin scattering turns complex at strong coupling: the key to pseudogap and Fermi arcs in the Hubbard model

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

Recent Developments and Future Directions

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