Ab initio calculation of dynamic polarizability and dielectric constant of carbon and silicon cubic crystals

Abstract

Valence and conduction bands of carbon silicon cubic systems are first obtained by a process called linear combination of atomic orbitals self‐consistent field (LCAO‐SCF), both at the Hartree‐Fock (HF) and local density approximation (LDA) levels. Then, the crystalline orbitals are used in a sum‐over‐states (SOS) method to calculate the corresponding dielectric constants related to electronic polarizabilities. This method allows parallel computations with large granularity of the optical properties and leads to uncoupled HF and LDA results. © 1997 John Wiley & Sons, Inc. J Comput Chem 18: 1253–1263, 1997

Study of absorption spectra and (hyper)polarizabilities of SiCn and SinC (n=2–6) clusters using density functional response approach

“…The ͗␣͘ values of the Si n C clusters ͑ϳ4.0 Å 3 / atom͒ are larger than those of the SiC n clusters; however, the ͗␣͘ values of the SiC n clusters increase with the cluster size and become close to those of the Si n C clusters. As in the case of the small Si clusters, 41 69 Similar behavior was also found for the bulk polarizabilities by Ayma et al 70 who theoretically gave the order of ␣͑Silicon͒ Ͻ ␣͑3C-SiC͒ Ͻ ␣͑Diamond͒. Direct experimental determination of the average polarizability is possible only for clusters whose dipole moment is zero.…”

Ab initioself-consistent calculations of the Compton profiles and polarizabilities of diamond and cubic boron nitride

“…In the following, every n is equal to one small arbitrary 1 value which leads to peak widths qualitatively comparable with those obtained for other cubic systems [48] and which avoids the poles problem (see also the Padé approximant method in reference [49]). In order to calculate this expression, equation (9), which generally converges slowly with the number of excited states (n), the uncoupled Hartree-Fock (UCHF) or uncoupled KS (UCKS) methods already described in reference [36] are used. In these methods, E n and f n are given by…”

“…To calculate the polarizability and its related functions, the uncoupled Hartree-Fock (UCHF) or uncoupled Kohn-Sham (UCKS) schemes already described [36] are used.…”

First-principles calculations of nonlinear optical susceptibility of inorganic materials

“…It may be noted here the dipole transition integrals over Bloch functions in a periodic solid are not defined uniquely in the length gauge. This problem, as described before, can be solved by setting the original cell of g to be zero [23,24]. That is, we can write…”

“…Finally, we identify the distinct physical contributions arising from the optical perturbation to the crystal susceptibility. In general, the derived formulae for the second-order response include various terms, and their partition into the so-called intraband and interband terms is rather conventional and depends somewhat on the formulation of the problem [2,5,23]. In the present model, χ vc represents an interband process of transitions from the valence to conduction bands (see equation (11)) and its value is directly related to changes in the crystal orbital dipole moments occurring during the transition (i.e.…”