A class of spintronic materials, the zinc-blende (ZB) half metals, has recently been synthesized in thin-film form. We apply all-electron and pseudopotential ab initio methods to investigate electronic structural properties ZB Mn Cr pnictides carbides, find six compounds be metallic at or near their respective equilibrium lattice constants, making them excellent candidates for growth low strain. Based on these findings, we further propose substrates which may accomplished with minimum Our...

A detailed discussion of quantum-size effects and the dimensionality in simple (s-p bonded) metals is presented by using aluminum as a prototype. The density states, work function, surface energy, relaxation, subband energies are calculated for films varying thicknesses. Oscillatory variations various physical properties correlate well with charge which itself varies film thickness. All calculations performed self-consistent pseudopotential method planarly averaged one-dimensional potential...

Neither local modes nor extended phonons precisely describe the excitations of anharmonic solids. A simple model Hamiltonian presented here characterizes transition from oscillator to optical phonon which would take place if one could continuously increase dispersion. The is used two types transitions: a phonon-localization analog Mott for electrons, and spectral associated with appearance two-phonon bound states. In real materials, sharp probably not achievable, but striking effects may be...

The energy band structure and optical properties of the zinc-blende semiconductors $3C$-SiC, BP, BN have been calculated using a nonlocal version empirical-pseudopotential method. results this investigation are discussed compared to experiment. agreement between theory experiment is found be very good for both SiC BP. quite rough, owing some questionable assumptions made necessary because scarcity experimental data. However, seem give reasonable first approximation correct structure. effect...

The local-empirical-pseudopotential method is used to calculate the electronic band structure of Sn${\mathrm{S}}_{2}$ and Sn${\mathrm{Se}}_{2}$. pseudopotential form factors for constituent elements Sn, S, Se are determined from previous calculations other crystals. Slight adjustments were made give correct fundamental gaps. A group-theoretical study symmetry properties these crystals included. imaginary part dielectric function, ${\ensuremath{\epsilon}}_{2}(\ensuremath{\omega})$, calculated...

A simplified model for the electronic structure of Chevrel-phase compound Pb${\mathrm{Mo}}_{6}$${\mathrm{S}}_{8}$ is obtained by means a tight-binding calculation cubic ${\mathrm{Mo}}_{6}$${\mathrm{S}}_{8}$ cluster. The interaction parameters this cluster are derived from fit to results an ab initio augmented-plane-wave energy-band hypothetical ${\mathrm{Mo}}_{3}$S crystal with ${\mathrm{Cu}}_{3}$Au structure. It found that molecular-orbital states near Fermi level ${E}_{F}$ consist...

The electronic band structure and optical constants of diamond are calculated using the empirical-pseudopotential method with an additional $\ensuremath{\ell}=1$ nonlocal term ${V}_{\mathrm{NL}}(\stackrel{\ensuremath{\rightarrow}}{r})$ added to account for strong potential experienced by $p$ electrons in core region. strongly affects $p$-like conduction bands, resulting yields a plot ${\ensuremath{\epsilon}}_{2}(\ensuremath{\omega})$, imaginary part dielectric function, which is satisfactory...

We present an approach to solid-state electronic-structure calculations based on the finite-element method. In this method, basis functions are strictly local, piecewise polynomials. Because is composed of polynomials, method completely general and its convergence can be controlled systematically. local in real space, allows for variable resolution space; produces sparse, structured matrices, enabling effective use iterative solution methods; well suited parallel implementation. The thus...

Ab initio calculations show that a spherically symmetric charge relaxation of ions in crystal, response to the long-range electrostatic potential, is important for understanding splitting between longitudinal- and transverse-optic-mode frequencies, violation Cauchy relations among elastic constants.

The nonlinear optical susceptibilities, $|{\ensuremath{\chi}}_{14}^{(2)}(2\ensuremath{\omega})|$ for second-harmonic generation of GaAs, InAs, and InSb in the range $0.05\ensuremath{\le}\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\le}3.0$ eV are calculated from band structure obtained by empirical pseudopotential method. spin-orbit interaction has been taken into account, transitions top four valence bands to bottom conduction included calculation. with...

The optical reflectivities of face-centered-cubic TiC and ZrC have been measured in the range $1.0\ensuremath{\le}\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\le}8.0$ eV. In addition, electronic-energy-band structures for these compounds calculated using a modified empirical-pseudopotential method, derived from band show approximate one-to-one correspondence to data, with agreement order 0.2 Prominent both are identified.

The electronic band structure of MgO is computed using the empirical pseudopotential method. resulting energy bands are then used to calculate optical constants over a wide range in energy. calculated real and imaginary parts dielectric function, reflectivity, part inverse function. Optical interband transitions identified, comparison between experiment theory made.

The electronic band structure of copper is calculated using the empirical pseudopotential method. A nonlocal $d$-wave potential with a damping factor used to provide for $d$ electron. results agree well available experimental data and theoretical calculations other methods. It anticipated that method can be noble metals even extended metal compounds, transition metals, compounds.

The wavelength modulation spectrum of Cu is presented at 7\ifmmode^\circ\else\textdegree\fi{}K in the range $2.0<~\ensuremath{\hbar}\ensuremath{\omega}<~6.0$ eV. band structure calculated by empirical pseudopotential method used to compute imaginary part dielectric function ${\ensuremath{\epsilon}}_{2}(\ensuremath{\omega})$ and logarithmic derivative reflectivity, $\frac{{R}^{\ensuremath{'}}(\ensuremath{\omega})}{R(\ensuremath{\omega})}$. Good agreement between theory experiment...

Due to their similarities metastable zinc-blende half-metals, we systematically examined the half-Heusler compounds $\ensuremath{\beta}\text{-LiMn}Z$ ($Z=\text{N},\text{P}$ and Si) for electronic, magnetic, stability properties at optimized lattice constants strained that exhibit half-metallic properties. We also report other phases of structure ($\ensuremath{\alpha}$ $\ensuremath{\gamma}$ phases), but they are unlikely be grown. The magnetic moments these stable Li-based expected reach as...

The electronic band structure and optical constants of NaCl KCl are calculated using the empirical pseudopotential method (EPM). was standard EPM; however, for we have added a nonlocal $d$-wave potential similar to that used by Falicov Lee potassium. prominent in measured spectrum these crystals is identified.

The structures and energetics of Pt, Pd, Ni adatom clusters on the Pt(001) surface have been investigated using embedded-atom method (EAM). stable configurations Pt are predicted to be linear chains oriented along 〈110〉 directions for three five adatoms close-packed islands four six or more adatoms. These results in agreement with a recent field-ion-microscopy (FIM) study previous EAM calculations [Schwoebel et al., Phys. Rev. B 40, 10 639 (1989)]. For except adatoms, which chain is...

We propose and investigate the properties of a digital ferromagnetic heterostructure (DFH) consisting $\delta$-doped layer Mn in Si, using \textit{ab initio} electronic-structure methods. find that (i) order is energetically favorable relative to antiferromagnetic, (ii) two-dimensional half metallic system. The behavior contributed by three majority-spin bands originating from hybridized Mn-$d$ nearest-neighbor Si-$p$ states, corresponding carriers are responsible for layer. minority-spin...

A seven-layer slab was used to model the ideal GaAs(110) surface. Two coverages, ${\ensuremath{\Theta}}_{t}$=1/2 and 1 monolayer (ML) of Na atoms on surface were studied. The total-energy calculations with self-consistent pseudopotential method determine positions We find that charge transfer is from Ga atoms. shift Fermi level respect valence-band maximum coverage 1/2 ML 0.33 eV downward. This result agrees reasonably measured value 0.2 for n-type

The self-consistent pseudopotential method has been used to calculate the electronic structure of periodic models amorphous hydrogenated silicon containing 7-13 at.% hydrogen, both as monohydride and dihydride. total density states, involving almost entirely valence electrons, two unequal maxima in occupied region, followed by a region very low (possibly zero) before rising again rapidly energy range that is empty electrons ground state. These features vary only little from one example...

Abstract The band structure of BiI 3 is calculated using the empirical pseudopotential method (EPM). Measurements reflectivity and wavelength modulated spectra at liquid helium temperatures are presented. For energies below 4.5 eV, fair agreement obtained between experimental theoretical spectra. valence density compared to recent X‐ray photoemission (XPS) data. Charge distributions distinct groups bands combined with states spectrum. These used explain nature chemical bonding in .

Anomalous $S$-shaped deviations from Vegard's law in some semiconductor alloys are attributed to the effect of bond-bending forces. This idea is substantiated by numerical calculations on two-dimensional model alloys. A criterion found which separates occurrence usually observed concave bowing and deviations. In addition, our results show that distribution bond lengths an alloy bimodal.