Dynamical Correlation Effects on the Quasiparticle Bloch States of a Covalent Crystal

Strinati, G. C.; Mattausch, Hj.; Hanke, W.

doi:10.1103/physrevlett.45.290

Cited by 192 publications

(137 citation statements)

References 23 publications

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“…Quasiparticle damping times were calculated for diamond by Strinati et al (1980Strinati et al ( , 1982, who found results consistent with photoemission data. A treatment of the electron dynamics, including band structure and dynamical screening effects, is necessary for quantitative comparisons with experiment (see, for instance, Bü rgi et al, 1999;Valla et al, 1999b).…”

Section: A Evaluation Of the Green's Function Gmentioning

confidence: 67%

“…It was shown that the GW approach managed to correct the largest part of the band-gap error; in fact, for the example of the gap at ⌫ in diamond, Strinati et al (1980) found a value of 7.4 eV, which is half of the Hartree-Fock gap and very close to the experimental one. 3 The fact that the inclusion of dynamical effects in the response functions leads to a reduction of the quasiparticle gap with respect to the static COHSEX result is a general finding, and the example of diamond shows the typical order of magnitude of the dynamical effects (i.e., about 10-20 % of the experimental gap).…”

Section: Effective Hamiltonians and Effective Interactionsmentioning

confidence: 98%

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Electronic excitations: density-functional versus many-body Green’s-function approaches

2002

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Electronic excitations lie at the origin of most of the commonly measured spectra. However, the first-principles computation of excited states requires a larger effort than ground-state calculations, which can be very efficiently carried out within density-functional theory. On the other hand, two theoretical and computational tools have come to prominence for the description of electronic excitations. One of them, many-body perturbation theory, is based on a set of Green's-function equations, starting with a one-electron propagator and considering the electron-hole Green's function for the response. Key ingredients are the electron's self-energy ⌺ and the electron-hole interaction. A good approximation for ⌺ is obtained with Hedin's GW approach, using density-functional theory as a zero-order solution. First-principles GW calculations for real systems have been successfully carried out since the 1980s. Similarly, the electron-hole interaction is well described by the Bethe-Salpeter equation, via a functional derivative of ⌺. An alternative approach to calculating electronic excitations is the time-dependent density-functional theory (TDDFT), which offers the important practical advantage of a dependence on density rather than on multivariable Green's functions. This approach leads to a screening equation similar to the Bethe-Salpeter one, but with a two-point, rather than a four-point, interaction kernel. At present, the simple adiabatic local-density approximation has given promising results for finite systems, but has significant deficiencies in the description of absorption spectra in solids, leading to wrong excitation energies, the absence of bound excitonic states, and appreciable distortions of the spectral line shapes. The search for improved TDDFT potentials and kernels is hence a subject of increasing interest. It can be addressed within the framework of many-body perturbation theory: in fact, both the Green's functions and the TDDFT approaches profit from mutual insight. This review compares the theoretical and practical aspects of the two approaches and their specific numerical implementations, and presents an overview of accomplishments and work in progress. CONTENTS

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Section: A Evaluation Of the Green's Function Gmentioning

confidence: 67%

Section: Effective Hamiltonians and Effective Interactionsmentioning

confidence: 98%

Electronic excitations: density-functional versus many-body Green’s-function approaches

2002

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show abstract

“…The use of the screened Coulomb interaction W, instead of the bare Coulomb interaction v, remedies this issue [2] and consequently, a comprehensive perturbative approach based on W can be derived [5]. Its first-order approximation, namely the GW approximation, has been used with great success for the last 30 years in extended systems to calculate the band gaps of solids [6,7,8,9]. In the past, the application of the GW approximation to finite systems was rather infrequent [10,11,12,13].…”

Section: General Presentationmentioning

confidence: 99%

molgw 1: Many-body perturbation theory software for atoms, molecules, and clusters

Bruneval

Rangel

Hamed

et al. 2016

Computer Physics Communications

181

238

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“…[8] In order to further improve the sX-LDA method or to come up with alternative methods, it is essential to understand the successes and failures of the current sX-LDA method by comparing with more accurate methods. For the single particle eigenvalues and the related GKS equations, we compare the sX-LDA method with the GW method [9][10][11][12][13][14][15], especially for the nonlocal potentials. For the total energy calculations and exchange-correlation holes, we compare sX-LDA with quantum Monte Carlo simulations.…”

Section: Introductionmentioning

confidence: 99%

Nonlocal exchange correlation in screened-exchange density functional methods

et al. 2007

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We present a systematic study on the exchange-correlation effects in screened-exchange local density functional method. To investigate the effects of the screened-exchange potential in the band gap correction, we have compared the exchange-correlation potential term in the sX-LDA formalism with the self-energy term in the GW approximation. It is found that the band gap correction of the sX-LDA method primarily comes from the downshift of valence band states, resulting from the enhancement of bonding and the increase of ionization energy. The band gap correction in the GW method, on the contrary, comes in large part from the increase of the conduction band energies. We also studied the effects of the screened-exchange potential in the total energy by investigating the exchange-correlation hole in comparison with quantum Monte Carlo calculations.When the Thomas-Fermi screening is used, the sX-LDA method overestimates (underestimates) the exchange-correlation hole in short (long) range. From the exchange-correlation energy analysis we found that the LDA method yields better absolute total energy than sX-LDA method.

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Dynamical Correlation Effects on the Quasiparticle Bloch States of a Covalent Crystal

Cited by 192 publications

References 23 publications

Electronic excitations: density-functional versus many-body Green’s-function approaches

Electronic excitations: density-functional versus many-body Green’s-function approaches

molgw 1: Many-body perturbation theory software for atoms, molecules, and clusters

Nonlocal exchange correlation in screened-exchange density functional methods

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