F. Benkabou

Atomistic study of zinc-blende CdS, CdSe, ZnS, and ZnSe from molecular dynamics

Abstract Empirical interatomic potential parameters are determined for group semiconductors such as CdS, CdSe, ZnS, and ZnSe. The structural properties of zinc-blende CdS, CdSe, ZnS, and ZnSe are calculated. A good agreement between the calculated and experimental values of the lattice constant, the cohesion energy, and bulk modulus and its derivative are obtained. The versality of these empirical potential parameters is confirmed by the calculation of elastic constants for CdS, CdSe, ZnS, and ZnSe. We have used the molecular-dynamics methods for the calculations of the thermal expansion and heat capacity. The results compare well with available results.

Elastic Properties of Zinc-blende G a N, A l N and I n N from Molecular Dynamics

Molecular dynamics calculations of the adiabatic elastic constants of group III-Nitrides for temperatures ranging from 300 to 900 K have been performed. The results show good agreement with first-principles calculations. The moduli decreased with increasing temperature. The structural properties of zinc-blende GaN, AlN and InN are reported. Good agreement between the calculated and experimental values of the lattice constant, the cohesion energy, and the bulk modulus and its derivative are obtained.

Energy band structure calculation of GexSn1−x and SixSn1−x alloys

Starting from band structures of the constituent materials, the electronic band structure of the semiconducting alloys GexSn1−x and SixSn1−x are calculated by the empirical pseudopotential method using a corrected virtual crystal approximation (VCA) which incorporates compositional disorder as an effective potential. Various quantities, including the bowing parameter of the fundamental band gap, the energies of several optical gaps, and the crossover of the band gaps are predicted.

Structural and dynamical properties of zincblende GaN

The structural and dynamical properties of zincblende β-GaN are calculated within a three-body Tersoff potential coupled with a molecular-dynamics simulation scheme for a temperature ranging from 300 to 900 K. A good agreement between the calculated and experimental values of the lattice constant, the bulk modulus and its derivative, and the cohesion energy are obtained. We have also calculated the lattice constants, lattice thermal expansion, and specific heat. In order to elucidate the microscopic behavior of mobile atoms with temperature, the diffusion mechanism has been predicted using this scheme. The structural properties of GaN in the rocksalt structure are also studied and compared with other works.

Composition dependence of the positron annihilation in Zn1−xMgxSe

Abstract In order to clarify the electronic and optical properties of wide-energy gap zinc-blende structure ZnSe, MgSe and their alloys, a simple pseudopotential scheme, with an affective potential the virtual crystal approximation which incorporates compositional disorder, is presented. The angular correlation of positron annihilation radiation along different crystallographic directions in Zn1−xMgxSe is calculated. We observe that the electron–positron momentum density decreases rapidly with increasing magnesium content.

Positron Annihilation Studies in SixSn1—x and GexSn1—x Alloys

The angular correlation of positron annihilation radiation (ACPAR) along different crystallographic directions in Si x Sn 1-x and Ge x Sn 1-x is calculated. We observe that the electron-positron momentum density increases rapidly with increasing Si and Ge content. The computational technique used here is based on the independent-particle model (IPM) coupled with the use of the electron pseudowave and the virtual crystal approximation (VCA) which incorporates compositional disorder as an effective potential. We also present the variation of the positron lifetime in these alloys.

Pressure dependence of positron distribution in Si

Abstract We have obtained the valence electron and positron charge densities in Si from wavefunctions derived in a model pseudopotential band structure calculation at normal and under hydrostatic pressure. We find that the positron density is maximum in the open interstices and is excluded not only, as usual, from the ion cores but also to a considerable degree from the valence bonds.

Theoretical Studies of Positron Annihilation in GaP1—xNx

Angular correlation of positron annihilation radiation (ACPAR) along different crystallographic directions in GaP 1-x N x is calculated. It is observed that the electron-positron momentum density increases rapidly with increasing nitrogen content. The computational technique used here is based on the independent-particle model (IPM) coupled with the use of the electron pseudo-wave function and the virtual crystal approximation (VCA) which incorporates compositional disorder as an effective potential. The variation of the positron lifetime in these alloys is also presented.