Elimination of the linearization error and improved basis-set convergence within the FLAPW method

Michalicek, Gregor; Betzinger, Markus; Friedrich, Christoph; Blügel, Stefan

doi:10.1016/j.cpc.2013.07.002

Cited by 32 publications

(45 citation statements)

References 27 publications

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“…Adopting a notation that is common to all flavors of the LAPW method, 52,54,55 the Bloch orbitals (n is the band index and k is a vector in the first Brillouin zone) are expanded as…”

Section: Methodsmentioning

confidence: 99%

Simple way to apply nonlocal van der Waals functionals within all-electron methods

et al. 2017

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The method based on fast Fourier transforms proposed by G. Román-Pérez and J. M. Soler [Phys. Rev. Lett. 103, 096102 (2009)], which allows for a computationally fast implementation of the nonlocal van der Waals (vdW) functionals, has significantly contributed to making the vdW functionals popular in solid-state physics. However, the Román-Pérez-Soler method relies on a planewave expansion of the electron density; therefore it can not be applied readily to all-electron densities for which an unaffordable number of plane waves would be required for an accurate expansion. In this work, we present the results for the lattice constant and binding energy of solids that were obtained by applying a smoothing procedure to the all-electron density calculated with the linearized augmented plane-wave method. The smoothing procedure has the advantages of being very simple to implement, basis-set independent, and allowing the calculation of the potential. It is also shown that the results agree very well with those from the literature that were obtained with the projector augmented wave method.

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“…Adopting a notation that is common to all flavors of the LAPW method, 52,54,55 the Bloch orbitals (n is the band index and k is a vector in the first Brillouin zone) are expanded as…”

Section: Methodsmentioning

confidence: 99%

Simple way to apply nonlocal van der Waals functionals within all-electron methods

et al. 2017

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“…The latter has been recently implemented in the WIEN2K code [43] as required for the accurate evaluation of NMR chemical shifts in the LAPW framework [44,45]. It should be noted that the importance of local orbitals for an accurate description of high-lying unoccupied states has been addressed by several authors in other contexts [46][47][48][49], and that the effects of including HLOs in the GW calculations for Si were already investigated by Blügel and co-workers in 2006 [14]. This paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

GWwith linearized augmented plane waves extended by high-energy local orbitals

2016

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Many-body perturbation theory in the GW approximation is currently the most accurate and robust firstprinciples approach to determine the electronic band structure of weakly correlated insulating materials without any empirical input. Recent GW results for ZnO with more careful investigation of the convergence with respect to the number of unoccupied states have led to heated debates regarding the numerical accuracy of previously reported GW results using either pseudopotential plane waves or all-electron linearized augmented plane waves (LAPWs). The latter has been arguably regarded as the most accurate scheme for electronic-structure theory for solids. This work aims to solve the ZnO puzzle via a systematic investigation of the effects of including high-energy local orbitals (HLOs) in the LAPW-based GW calculations of semiconductors. Using ZnO as the prototypical example, it is shown that the inclusion of HLOs has two main effects: it improves the description of high-lying unoccupied states by reducing the linearization errors of the standard LAPW basis, and in addition it provides an efficient way to achieve the completeness in the summation of states in GW calculations. By investigating the convergence of GW band gaps with respect to the number of HLOs for several other typical examples, it was found that the effects of HLOs are highly system-dependent, and in most cases the inclusion of HLOs changes the band gap by less than 0.2 eV. Compared to its effects on the band gap, the consideration of HLOs has even stronger effects on the GW correction to the valence-band maximum, which is of great significance for the GW prediction of the ionization potentials of semiconductors. By considering an extended set of semiconductors with relatively wellestablished experimental band gaps, it was found that in general using a HLO-enhanced LAPW basis significantly improves the agreement with experiment for both the band gap and the ionization potential, and overall the partially self-consistent GW 0 approach based on the generalized gradient approximation gives an optimal performance.

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“…A straightforward inclusion of all the products u l n u ln may lead to an excessively large and linearly dependent basis set. Here, we can take advantage of the fact that U ll nn (r) are restricted to a close vicinity of the potential singularity, where the radial solutions change very slowly with energy 23,34 , so the number of physically relevant u ln is much smaller. Moreover, their shape is determined by the potential singularity, and it is practically independent of the crystal potential.…”

Section: B Density Matrix Elementsmentioning

confidence: 99%

All-electron product basis set: Application to plasmon anisotropy in simple metals

Budagosky

Krasovskii

2019

Phys. Rev. B

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An efficient basis set for products of all-electron wave functions is proposed, which comprises plane waves defined over the entire unit cell and orbitals confined to small non-overlapping spheres. The size of the set and the basis functions are, in principle, independent of the computational parameters of the band structure method. The approach is implemented in the extended LAPW method, and its properties and accuracy are discussed. The method is applied to analyze the dielectric response of the simple metals Al, Na, Li, K, Rb, and Cs with a focus on the origin of the anisotropy of the plasmon dispersion in Al and Na. The anisotropy is traced to tiny structures of the one-particle excitation spectra of Al and Na, and relevant experimental observations are explained. arXiv:1904.00968v1 [cond-mat.mtrl-sci] 1 Apr 2019

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Elimination of the linearization error and improved basis-set convergence within the FLAPW method

Cited by 32 publications

References 27 publications

Simple way to apply nonlocal van der Waals functionals within all-electron methods

Simple way to apply nonlocal van der Waals functionals within all-electron methods

GWwith linearized augmented plane waves extended by high-energy local orbitals

All-electron product basis set: Application to plasmon anisotropy in simple metals

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