G. Satta

Electronic and structural properties of superconducting MgB2, CaSi2, and related compounds

We report a detailed study of the electronic and structural properties of the 39K superconductor \mgbtwo and of several related systems of the same family, namely \mgalbtwo, \bebtwo, \casitwo and \cabesi. Our calculations, which include zone-center phonon frequencies and transport properties, are performed within the local density approximation to the density functional theory, using the full-potential linearized augmented plane wave (FLAPW) and the norm-conserving pseudopotential methods. Our results indicate essentially three-dimensional properties for these compounds; however, strongly two-dimensional

Optical properties of BN in cubic and layered hexagonal phases

\sigma

Metal-induced gap states and Schottky barrier heights at nonreactive GaN/noble-metal interfaces

-bonding bands contribute significantly at the Fermi level. Similarities and differences between \mgbtwo and \bebtwo (whose superconducting properties have not been yet investigated) are analyzed in detail. Our calculations for \mgalbtwo show that metal substitution cannot be fully described in a rigid band model. \casitwo is studied as a function of pressure, and Be substitution in the Si planes leads to a stable compound similar in many aspects to diborides.

Fermi Surface Nesting and Magnetic Structure of ErGa3

INFM Sezione di Roma-2 and Dipartimento di Fisica, Universita`di Tor Vergata, Via della Ricerca Scientifica 1, I-00133, Rome, Italy~Received 24 January 2001; revised manuscript received 6 April 2001; published 26 June 2001!Linear optical functions of cubic and hexagonal BN have been studied within first principles density func-tional theory in the local density approximation. Calculated energy-loss functions show reasonable agreementwith experiments and previous theoretical results both for h-BN and forc-BN. Discrepancies arise betweentheoretical results and experiments in the imaginary part of the dielectric function for c-BN. Possible expla-nations of this mismatch are proposed and evaluated: lattice constant variations, h-BN contamination inc-BNsamples, and self-energy effects.DOI: 10.1103/PhysRevB.64.035104 PACS number~s!: 78.20.Ci, 68.35.Ja, 71.45.GmI. INTRODUCTION

Pressure- and strain-dependent quasiparticle energies of cubic, wurtzite and hexagonal BN

We present ab initio local density FLAPW calculations on nonreactive N-terminated [001] ordered GaN/Ag and GaN/Au interfaces and compare the results (such as metal induced gap states and Schottky barrier heights) with those obtained for GaN/Al, in order to understand the dependence of the relevant electronic properties on the deposited metal. Our results show that the density-of-gap states is appreciable only in the first semiconductor layer close to the interface. The decay length of the gap states in the semiconductor side is about

Fermi surface study ofLaRu2Si2and of heavy-fermionCeRu2Si2above the Kondo temperature

2.0\ifmmode\pm\else\textpm\fi{}0.1\AA{}

Ab initio optical properties of BN in the cubic and in the layered hexagonal phase

and is independent of the deposited metal, therefore being to a good extent a bulk property of GaN. Our calculated values of the Schottky barrier heights are

Cohesive Energies of Be and Mg Chalcogenides

{\ensuremath{\Phi}}_{{B}_{p}}(\mathrm{GaN}/\mathrm{Ag})=0.87\mathrm{eV}

Classical versus ab initio structural relaxation: electronic excitations and optical properties of Ge nanocrystals embedded in an SiC matrix

and

Ab-Initio Calculations for the Electronic Spectra of Cubic and Hexagonal Boron Nitride

{\ensuremath{\Phi}}_{{B}_{p}}(\mathrm{GaN}/\mathrm{Au})=1.08\mathrm{eV};