Tight Binding Version (tight + binding_version)

Distribution by Scientific Domains


Selected Abstracts


The electronic and electrochemical properties of the TiFe1,xNix alloys

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
A. Szajek
Abstract Mechanical alloying (MA) process was introduced to produce nanocrystalline TiFe1,xNix alloys (0 , x , 1). XRD analysis showed that, firstly, after 25 h of milling, the starting mixture of the elements had decomposed into an amorphous phase and, secondly, the annealing in high purity argon at 750 °C for 0.5 h led to formation of the CsCl-type (B2) structures with a crystallite sizes of about 30 nm. These materials, used as negative electrodes for Ni,MH batteries, showed an increase in discharge capacity with a maximum for x = 3/4. The band structure has been studied by the Tight Binding version of the Linear Muffin-Tin method in the Atomic Sphere Approximation (TB LMTO ASA). Increasing content of Ni atoms intensified charge transfer from Ti atoms, extended valence bands and increased the values of the densities of electronic states at the Fermi level. [source]


The electronic and electrochemical properties of the LaNi5 -based alloys

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
A. Szajek
Abstract Nanocrystalline La(Ni,M)5 -type alloys were prepared by mechanical alloying (MA) and subsequent annealing. The alloying elements of 3d transition metals, Mn, Al and Co were substituted for Ni in LaNi5, and the structural, electrochemical as well as electronic properties were studied. It was found that the partial substitution of Ni by Al or Mn in nanocrystalline La(Ni,M)5 alloy leads to an increase in the discharge capacity. On the other hand, cobalt substituting nickel in LaNi4,xMn0.75Al0.25Cox alloy greatly improved the discharge capacity and cycle life of LaNi5 material. The electronic structure has been studied by the tight binding version of the linear muffin-tin orbital method (TB LMTO) for La(Ni0.8,xCoxAl0.1Mn0.1)5 systems, where x = 0, 0.1, 0.2, and 0.3. [source]


Properties of the UFe5Sn compound: electronic structureand X-ray photoemission

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003
A. Szajek
Abstract The UFe5Sn compound crystallizes in the orthorhombic CeCu5Au-type structure having the Pnma space group with iron atoms located in four inequivalent sites. The electronic structure UFe5Sn compound has been studied using spin-polarized tight binding version of the linear muffin-tin orbital method in the atomic sphere approximation (TB LMTO ASA). The calculations showed that the magnetic moments on uranium atoms are antiparallel to the moments formed on Fe atoms, whose values depend on local environments. The X-ray photoemission spectra were calculated. [source]


Electronic structure of the uranium monostannide USn

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003
A. Szajek
Abstract The uranium monostannide USn crystallizes in the orthorhombic ThIn-type structure (Pbcm space group) in which the uranium and tin atoms each occupy three crystallographic positions. The electronic structure of USn compound has been studied using spin-polarized tight binding version of the linear muffin-tin orbital method in the atomic sphere approximation (TB LMTO ASA). The calculations showed that all three types of uranium atoms are magnetically ordered and their moments depend on local environments. [source]