Space-Time Method for<i>Ab Initio</i>Calculations of Self-Energies and Dielectric Response Functions of Solids

Rojas, H.; Godby, R. W.; Needs, R. J.

doi:10.1103/physrevlett.74.1827

Cited by 246 publications

(325 citation statements)

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“…24 Mixed-space (Blase et al, 1995) and real-space/imaginarytime techniques (Rojas et al, 1995), as well as a technique to eliminate the unoccupied state summations , can also be used to reduce the computational effort (see the reviews by Aulbur et al, 1999;and Aryasetiawan and Gunnarsson, 1998, for a detailed comparison of different numerical implementations).…”

Section: A Evaluation Of the Green's Function Gmentioning

confidence: 99%

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: 99%

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

2002

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“…7,10,17,18,19,20,21 In particular, Aryasetiawan has approximately determined the screening within the RPA using a linear muffin-tin orbital method within the atomic sphere approximation 7 ( LMTO-ASA). This method, although fast, approximates the space by atomic centered overlapping spheres, thus completely neglecting the interstitial region, and hence making the reliability of the GW method uncertain.…”

Section: Introductionmentioning

confidence: 99%

Implementation of an all-electron GW approximation based on the projector augmented wave method without plasmon pole approximation: Application to Si, SiC, AlAs, InAs, NaH, and KH

et al. 2003

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A new implementation of the GW approximation (GWA) based on the all-electron ProjectorAugmented-Wave method (PAW) is presented, where the screened Coulomb interaction is computed within the Random Phase Approximation (RPA) instead of the plasmon-pole model. Two different ways of computing the self-energy are reported. The method is used successfully to determine the quasiparticle energies of six semiconducting or insulating materials: Si, SiC, AlAs, InAs, NaH and KH. To illustrate the novelty of the method the real and imaginary part of the frequency-dependent self-energy together with the spectral function of silicon are computed. Finally, the GWA results are compared with other calculations, highlighting that all-electron GWA results can differ markedly from those based on pseudopotential approaches.

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“…In contrast, manybody perturbation theory within Hedin's GW approximation 16,17 presents a unique framework that allows access to both quasi-particle (QP) energies and lifetimes on the same footing. This method has been successfully applied to quasi-1D, 2D and 3D semiconductors, insulators, and metals [18][19][20][21][22][23] , and very recently to molecular systems [24][25][26][27][28][29][30][31][32][33] .…”

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confidence: 99%

Photoelectron properties of DNA and RNA bases from many-body perturbation theory

2011

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The photoelectron properties of DNA and RNA bases are studied using many-body perturbation theory within the GW approximation, together with a recently developed Lanczos-chain approach. Calculated vertical ionization potentials, electron affinities, and total density of states are in good agreement with experimental values and photoemission spectra. Convergence benchmark demonstrates the importance of using an optimal polarizability basis in the GW calculations. A detailed analysis of the role of exchange and correlation in both many-body and density-functional theory calculations shows that while self-energy corrections are strongly orbital-dependent, they nevertheless remain almost constant for states that share the same bonding character. Finally, we report on the inverse lifetimes of DNA and RNA bases, that are found to depend linearly on quasi-particle energies for all deep valence states. In general, our G0W0-Lanczos approach provides an efficient yet accurate and fully-converged description of quasiparticle properties of five DNA and RNA bases.

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Space-Time Method forAb InitioCalculations of Self-Energies and Dielectric Response Functions of Solids

Cited by 246 publications

References 9 publications

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

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

Implementation of an all-electron GW approximation based on the projector augmented wave method without plasmon pole approximation: Application to Si, SiC, AlAs, InAs, NaH, and KH

Photoelectron properties of DNA and RNA bases from many-body perturbation theory

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