Radial distribution functions of<i>ab initio</i>generated amorphous covalent networks

Álvarez, F.; Díaz, Carlos; Valladares, Ariel A.; Valladares, R.M.

doi:10.1103/physrevb.65.113108

Cited by 37 publications

(25 citation statements)

References 35 publications

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“…[41]), reflecting the common type of short-range arrangement of atoms based on the tetrahedral unit. Similar conclusions were obtained for the electronic DOS calculated through an approximate density-functional Scheme [42] and through a tight binding approach [43]. Moreover, the calculated valence band is consistent with photoemission spectra [44].…”

Section: Electronic Structuresupporting

confidence: 80%

“…However, we note that the band gap is quite sensitive to the adopted production method and for CVD samples is about 5.3 eV [46]. Yet, the GW method appears to correctly describe the electronic DOS where simpler LDA calculations fail giving for our model structure a HOMO-LUMO band-gap of only 2.9 eV, as typical for LDA calculations in silicon nitride [38,42]. We now analyze the degree of localization of the electronic states.…”

Section: Electronic Structurementioning

confidence: 91%

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Accelerating GW calculations with optimal polarizability basis

Umari¹,

Qian²,

Marzari³

et al. 2010

Physica Status Solidi (b)

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We present a method for accelerating GW quasi-particle (QP) calculations. This is achieved through the introduction of optimal basis sets for representing polarizability matrices. First the real-space products of Wannier like orbitals are constructed and then optimal basis sets are obtained through singular value decomposition. Our method is validated by calculating the vertical ionization energies of the benzene molecule and the band structure of crystalline silicon. Its potentialities are illustrated by calculating the QP spectrum of a model structure of vitreous silica. Finally, we apply our method for studying the electronic structure properties of a model of quasi-stoichiometric amorphous silicon nitride and of its point defects.

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Section: Electronic Structuresupporting

confidence: 80%

Section: Electronic Structurementioning

confidence: 91%

Accelerating GW calculations with optimal polarizability basis

Umari¹,

Qian²,

Marzari³

et al. 2010

Physica Status Solidi (b)

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show abstract

“…These calculations use ab initio molecular dynamics and electronic density functional theory, but in a localized basis. A recent study, in which S(k) and g(r) were computed for several ab initio structural models of a-Si, has been carried out by Alvarez et al [23].…”

Section: Introductionmentioning

confidence: 99%

Dynamic structure factor of liquid and amorphous Ge fromab initiosimulations

et al. 2003

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We calculate the dynamic structure factor S(k, ω) of liquid Ge (ℓ-Ge) at temperature T = 1250 K, and of amorphous Ge (a-Ge) at T = 300 K, using ab initio molecular dynamics. The electronic energy is computed using density-functional theory, primarily in the generalized gradient approximation, together with a plane wave representation of the wave functions and ultra-soft pseudopotentials. We use a 64-atom cell with periodic boundary conditions, and calculate averages over runs of up to about 16 ps. The calculated liquid S(k, ω) agrees qualitatively with that obtained by Hosokawa et al, using inelastic X-ray scattering. In a-Ge, we find that the calculated S(k, ω) is in qualitative agreement with that obtained experimentally by Ma- * Present address:

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“…The reason for using a standard set is that, within our approximations, these orbitals give the correct position of the first peak of the resulting amorphous structure [18]. The minimal basis sets do not reproduce this position adequately [19].…”

Section: Methodsmentioning

confidence: 94%