Theory of optically forbidden d–d transitions in strongly correlated crystals

Katsnelson, M. I.; Lichtenstein, A. I.

doi:10.1088/0953-8984/22/38/382201

Cited by 15 publications

(12 citation statements)

References 24 publications

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“…However, among various long-range fluctuations this approach considers only collective charge excitations and does not account for vertex corrections. The latter are important for an accurate description of magnetic, optical and transport properties of the system [45][46][47][48][49][50][51][52][53][54][55]. More elaborate theories like DF, DB, and DΓA, which address all leading collective fluctuations on equal footing, account for vertex corrections and appear to be in a good agreement with numerically exact methods [4,[37][38][39]56].…”

Section: Introductionmentioning

confidence: 86%

Impact of partially bosonized collective fluctuations on electronic degrees of freedom

et al. 2021

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In this work we present a comprehensive analysis of collective electronic fluctuations and their effect on single-particle properties of the Hubbard model. Our approach is based on a standard dual fermion/boson scheme with the interaction truncated at the two-particle level. Within this framework we compare various approximations that differ in the set of diagrams (ladder vs exact diagrammatic Monte Carlo), and/or in the form of the four-point interaction vertex (exact vs partially bosonized). This allows to evaluate the effect of all components of the four-point vertex function on the electronic self-energy. In particular, we observe that contributions that are not accounted for by the partially bosonized approximation for the vertex have only a minor effect on electronic degrees of freedom in a broad range of model parameters. In addition, we find that in the regime, where the ladder dual fermion approximation provides an accurate solution of the problem, the leading contribution to the self-energy is given by the longitudional bosonic modes. This can be explained by the fact that contributions of transverse particle-hole and particle-particle modes partially cancel each other. Our findings justify applicability of the recently introduced dual triply irreducible local expansion (D-TRILEX) method that provides one of the simplest consistent diagrammatic extensions of the dynamical mean-field theory.

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Section: Introductionmentioning

confidence: 86%

Impact of partially bosonized collective fluctuations on electronic degrees of freedom

et al. 2021

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“…The combination of the DMFT approach with realistic electronic structure calculations [10,11], in particular, for transition metal systems [5,12] opens a new way for the description of electronic degrees of freedom in solids. A generalization of the DMFT approach to non-local interactions and consistent description of collective bosonic excitations [10,13,14,15] boost first realistic applications of a so-called GW+DMFT approach [16].…”

Section: Introductionmentioning

confidence: 99%

Dual boson approach to collective excitations in correlated fermionic systems

2012

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We develop a general theory of a boson decomposition for both local and non-local interactions in lattice fermion models which allows us to describe fermionic degrees of freedom and collective charge and spin excitations on equal footing. An efficient perturbation theory in the interaction of the fermionic and the bosonic degrees of freedom is constructed in so-called dual variables in the path-integral formalism. This theory takes into account all local correlations of fermions and collective bosonic modes and interpolates between itinerant and localized regimes of electrons in solids. The zero-order approximation of this theory corresponds to extended dynamical mean-field theory (EDMFT), a regular way to calculate nonlocal corrections to EDMFT is provided. It is shown that dual ladder summation gives a conserving approximation beyond EDMFT. The method is especially suitable for consideration of collective magnetic and charge excitations and allows to calculate their renormalization with respect to "bare" RPA-like characteristics. General expression for the plasmonic dispersion in correlated media is obtained. As an illustration it is shown that effective superexchange interactions in the half-filled Hubbard model can be derived within the dual-ladder approximation.

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“…bilayer graphene), transitionmetal dichalcogenides, and few-layer black-phosphorus. Also, it can be generalized [10][11][12] to take into account electron-electron interactions (plasmons, excitons, etc. ).…”

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confidence: 99%

Theory of third-harmonic generation in graphene: A diagrammatic approach

Rostami

Polini

2016

Phys. Rev. B

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We present a finite-temperature diagrammatic perturbation theory of third harmonic generation (THG) in doped graphene. We carry out calculations of the third-order conductivity in the scalar potential gauge, highlighting a subtle cancellation between a Fermi surface contribution, which contains only power laws, and power-law contributions of inter-band nature. Only logarithms survive in the final result. We conclude by presenting quantitative results for the up-conversion efficiency at zero and finite temperature. Our results shed light on the on-going dispute over the dependence of THG on carrier concentration in graphene.Introduction.-The non-linear optical properties of graphene 1 , the most studied two-dimensional (2D) material, are beginning to attract considerable interest. Using four-wave mixing, Hendry et al. 2 demonstrated experimentally that the third-order optical susceptibility of graphene is remarkably large (≈ 1.4 × 10 −15 m 2 /V 2 ) and only weakly dependent on wavelength in the nearinfrared frequency range. Third harmonic generation (THG) from mechanically exfoliated graphene sheets has been measured by Kumar et al. 3 who extracted a value of the third-order susceptibility on the order of 10 −16 m 2 /V 2 for an incident photon energy ω = 0.72 eV. Finally, Hong et al. 4 reported strong THG in graphene grown by chemical vapor deposition, in the situation in which the incident photon energy ω = 1.57 eV is in three-photon resonance with the exciton-shifted van Hove singularity.

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Theory of optically forbidden d–d transitions in strongly correlated crystals

Cited by 15 publications

References 24 publications

Impact of partially bosonized collective fluctuations on electronic degrees of freedom

Impact of partially bosonized collective fluctuations on electronic degrees of freedom

Dual boson approach to collective excitations in correlated fermionic systems

Theory of third-harmonic generation in graphene: A diagrammatic approach

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