This paper is a review article covering our work in recent years on PbTe and the alloy semiconductor CdXPbl-,Te. It shows how measurements of the transport and optical properties of these materials support (1) the two valence band model for PbTe in which the principal light mass band is highly non-parabolic and the secondary heavy mass band is parabolic and (2) a value for the Hall-anisotropy f...

The last decade has seen a large increase in the number of electronic-structure calculations that involve adding a Hubbard term to the local-density approximation band-structure Hamiltonian. The Hubbard term is then determined either at the mean-field level or with sophisticated many-body techniques such as using dynamical mean-field theory. We review the physics underlying these approaches and...

Investigation of the properties of MnxGa1-xN semiconductor alloy is performed on the basis of LCAO electron band structure of this semiconductor. The authors model this alloy on the basis of Mn substitutions on Ga sites and it is identified that the ternary semiconductor MnxGa1-xN has two tetrahedral binary constituents – GaN and MnN. It is found that the sp 3 hybrid orbital of the N atom attra...

this paper presents a new design for a microstrip dual-band band-pass microstrip filter (bpf) with suitable isolation between two passbands. in this design, a basic structure is used to achieve a desirable frequency characteristic in the passband. in this regard, defected ground structure (dgs) is implemented to reach optimum parameters of the filter such as bandwidth, return loss, insertion lo...

We have designed a new type of optical channel drop filter (CDF) based on two dimensionaltriangular lattice photonic crystals. CDF operation is based on coupling to the photonic crystalwaveguide. The proposed structure is optimized to work as a CDF for obtaining the CDFcharacteristics and band structure of the filter the finite difference time domain (FDTD) method andplane wave expansion (PWE) ...

the high pressure behavior of the structural and electronic properties of kc1 is studied with use of the density functional pseudopotential method within local-density approximation. atzero pressure, the rocksalt phase is found to be lower in energy than cscl structure. however, we predict a phase transition into csci structure at a pressure of about 1.5 gpa. the calculated ground state propert...

in this work facile sol-gel (pechni) method has been successfully established to synthesize zn4b6o13 nanocrystals which have cubic crystals with lattice parameter: a =7.48 a. the structure and morphology of the obtained material were studied by x-ray diffraction (xrd), infrared spectra (ir), scanning electron microscopy (sem) and photoluminescence analysis. the experimental results show a band ...