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Band Structure Calculations (band + structure_calculation)
Selected AbstractsUnpaired Spin Populations and Spin-Pairing Tendencies of the Nonequivalent Vanadium Sites of the Magnetic Metal NaV6O11 Investigated by Electronic Band Structure Calculations and Spin Dimer Analysis.CHEMINFORM, Issue 43 2005A. Villesuzanne No abstract is available for this article. [source] Thickness Dependent Loss Function of Si with 0.14 eV Energy ResolutionADVANCED ENGINEERING MATERIALS, Issue 10 2004M. Stöger-Pollach Si band gap spectra were recorded by using electron energy loss spectrometry with very high energy resolution of 0.14 eV using a transmission electron microscope with a monochromated electron source. The shape of the spectra change with thickness, becoming indistinct at very thin regions. But even for higher thicknesses structureal evolution of the spectra can be observed. A comparison with band structure calculations is given, too. [source] Electron Energy Loss SpectroscopyIMAGING & MICROSCOPY (ELECTRONIC), Issue 2 2007Chemical Information at the Nanometer Scale Abstract The combination of high resolution imaging with energy loss spectroscopy allows to resolve questions about the morphology, structure, composition and electronic structure of a material in a single instrument. By the assistance of band structure calculations and simulated EELS spectra, the experimental data can be analyzed in detail. Following this approach it is possible to study the relation between the geometric and electronic structure of materials at the nanometer scale. [source] Semiconducting half-Heusler and LiGaGe structure type compoundsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009Frederick Casper Abstract Compounds with LiAlSi (half-Heusler) and LiGaGe structure types have been investigated by means of band structure calculations. The LiAlSi structure type is known as the half-Heusler structure type, whereas LiGaGe is a closely related hexagonal variant. A remarkable feature of some XYZ half-Heusler compounds with 8 and 18 valence electrons is, that despite being composed of only metallic elements, they are semiconductors. More than 100 semiconducting compounds within these structure types are known. LiGaGe compounds have an additional degree of freedom, namely the degree of puckering of the layers. These compounds can become semiconducting at a certain degree of puckering. Half-metallic behavior is rarely found in this structure type. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] On the magnetic behaviour of GdCo2,xCux compoundsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003R. Tetean Abstract The GdCo2,xCux compounds crystallize in a cubic C15 type structure for x , 0.20. The compounds are ferrimagnetically ordered. The mean cobalt magnetic moments, determined at 4.2 K, are little dependent on composition. The saturation moments per formula unit, at 4.2 K, are in rather good agreement with those obtained from band structure calculations. The Gd 5d band polarizations were analyzed. The contributions from 4f,5d, local exchange M5d(Gd), and 5d,3d short range exchange interactions, M5d(0), were determined. The M5d(0) values are proportional to cobalt magnetizations. [source] How do electrons travel in unusual metallic fluorides of Ag2+?,PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2005Tomasz Jaro Abstract We investigate computationally two representative examples of higher fluorides of Ag(II), namely KAgF3 and AgFBF4. Both compounds formally contain linear (Ag,F)+ chains, in which divalent silver is coordinated additionally by four fluoride anions. For AgFBF4, the equatorial coordination is weak, and leads to metallic conductivity in 1D, as emerges from our band structure calculations. For KAgF3, however, the axial coordination is very strong, and the compound is virtually a 2D metal (i.e. it is mainly the x2,y2 orbitals of Ag that participate in electronic transport in this interesting material). (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] NMR properties of half-Heusler CoVSbPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2006H. Nishihara Abstract The complex NMR properties of CoVSb are reported. On the basis of band structure calculations the compound is predicted to be a half metallic ferromagnet but magnetisation measurements suggest that the compound is a weak ferromagnet. In zero applied field at 4.2 K, three spin echo signals have been observed with peak frequencies of 30, 63 and 82 MHz, which are tentatively assigned as signals associated with antimony, vanadium and cobalt atoms. The cobalt atoms are suggested to have moments of about 0.8 ,B. In addition three spin echo signals have been observed in swept applied fields at 4.2 K which include signals from non magnetic cobalt and vanadium sites. Thus weak ferromagnetism in CoVSb is concluded to be complex on a microscopic scale with the moment of 0.18 ,B per formula unit, obtained from static magnetic measurements, being the average moment of magnetic and nonmagnetic sites of cobalt and vanadium atoms. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Magnetic and XPS studies on TbNi5,xAlx systemPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2004E. Burzo Abstract Magnetic measurements were performed on TbNi5,xAlx system, in the temperature range 1.7,300 K. At T = 1.7 K the saturation magnetizations are smaller than gJJ value of Tb. The nickel moments at 0 K, determined by band structure calculations are antiparallely oriented to Tb one and decrease in magnitude, being essentially null for TbNi3Al2 sample. The effective nickel moments vary from 2.10 ,B (x = 0) to , 1.10 ,B (x = 2). The XPS studies show that the Ni2p core level lines are similar to those of pure Ni, although the intensities of Ni 6 eV satellite decrease. The valence band spectra suggest an increase of the Ni3d,Al3p hybridization, when increasing Al content, in agreement with band structure calculations. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Quasi-three-dimensional network of molecular interactions and electronic structure of a new organic semiconductor, ET(NCS)0.77ACTA CRYSTALLOGRAPHICA SECTION B, Issue 1 2002Olga N. Kazheva The radical cation salt ET(NCS)0.77 [bis(ethylenedithio)tetrathiafulvalene thiocyanate (1/0.77)] has been prepared for the first time by electrocrystallization and its crystal and electronic structure at 110,K was investigated. The unit-cell dimensions are orthorhombic, a = 6.638,(1), b = 8.309,(2), c = 28.776,(6),Å, V = 1587.1,(6),Å3, space group Pbcm, Z = 4. The compound has a layered structure. The ET radical cations of the conducting cationic layer build stacks. In the anionic layer the thiocyanate groups form polymeric chains where they are oriented in a `head-to-tail' mode. The structure has short intermolecular contacts of the cation,cation, anion,anion and cation,anion types, which leads to the formation of a three-dimensional structure of intermolecular interactions. This phenomenon is very rare in molecular conductors. Tight binding band structure calculations suggest, however, that the interlayer interactions through the anions are weak and that the incomplete occupation of the anion sites is the reason for the activated conductivity of the salt. [source] | |||||||||||||