Ab Initio Calculations of Structural Energetics of Transition-Metal Aluminides and Silicides

1990 ◽  
Vol 213 ◽  
Author(s):  
A. E. Carlsson ◽  
P. J. Meschter
Keyword(s):  
Transition Metal ◽  
Band Structure ◽  
Ab Initio Calculations ◽  
Fermi Level ◽  
Ab Initio ◽  
Density Of States ◽  
Band Structure Calculations ◽  
Total Energies ◽  
Metal Aluminides ◽  
Structure Calculations

ABSTRACTTotal energies of binary and ternary -metral trialminides in the L12DO22 Do23Structures and binary Transition- metal disilicides in the C1lb, C40, C54, and C49 structures have been obtained by ab initio band-structure calculations. In aluminides the tetragonal Do22 and Do23 structures are stabilized relative to cubic L12P and in silicides the hexagonal C40 structure is stabilized relative to orthorhombic C54 and tetragonal C11b relative to C40, as the transition-metal d-electron count increases. The observed easier stabilization of L12 in Ti(AI,Fe) 3 relative to Nb(AI,Fe)is justified by the calculations. Location of the Fermi level in a quasigap in the density of states distribution rationalizes the observed structural stabilities in aluminides but not in silicides.

PHYSICAL PROPERTIES OF AuAl2, AuGa2, AuIn2, AND PtGa2

1994 ◽  
Vol 08 (21n22) ◽  
pp. 1297-1318 ◽  
Author(s):  
LI-SHING HSU
Keyword(s):  
Thin Film ◽  
Optical Properties ◽  
Band Structure ◽  
Physical Properties ◽  
Fermi Level ◽  
Density Of States ◽  
Band Structure Calculations ◽  
Structure Calculations ◽  
Film Form

The structural, electronic, magnetic, and optical properties of AuAl 2, AuGa 2, AuIn 2, and PtGa2 are reviewed. These experimental results are compared with the values of the density of states at the Fermi level derived from band-structure calculations. The so-called “ AuGa 2 dilemma” and the controversial positions of the Au 5d bands in AuAl 2, AuGa 2, and AuIn 2 are discussed. The physical properties of PtGa 2 are summarized and compared with those of the Au intermetallic compounds. Recent researches on the growth and characterization of these compounds in thin-film form are also presented.

LCAO Ab Initio Band Structure Calculations for Polymers

1990 ◽  
pp. 745-783 ◽  
Author(s):  
J. M. André ◽  
J. L. Brédas ◽  
J. Delhalle ◽  
D. J. Vanderveken ◽  
D. P. Vercauteren ◽  
...  
Keyword(s):  
Band Structure ◽  
Ab Initio ◽  
Band Structure Calculations ◽  
Structure Calculations

The electronic structure of disordered system

1964 ◽  
Vol 279 (1376) ◽  
pp. 82-97 ◽  
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Density Of States ◽  
Disordered System ◽  
Perfect Lattice ◽  
Geometric Approximation ◽  
Band Structure Calculations ◽  
Interacting Electrons ◽  
Simplifying Assumptions ◽  
Structure Calculations

A general expression is written down for the density of states of non-interacting electrons in a disordered system. The expression is obtained on the basis of two simplifying assumptions; the geometric approximation, which is connected with the disorder, and an approximation concerning the potential which is commonly used in band structure calculations. In the case of a perfect lattice the result of Kohn & Rostoker (1954) for the band structure of the lattice is derived, and details of the density of states are available from the formula thus obtained. It is shown how the change in the energy of the electrons due to the presence of a phonon can be obtained.

Band theory of insulating transition-metal monoxides: Band-structure calculations

1984 ◽  
Vol 30 (8) ◽  
pp. 4734-4747 ◽  
Author(s):  
K. Terakura ◽  
T. Oguchi ◽  
A. R. Williams ◽  
J. Kübler
Keyword(s):  
Transition Metal ◽  
Band Structure ◽  
Band Theory ◽  
Band Structure Calculations ◽  
Structure Calculations

Magnetism in 4d Transition Metal–Ag(001) Sandwiches

1991 ◽  
Vol 231 ◽  
Author(s):  
Dennis P. Clougherty ◽  
M. E. Mchenry ◽  
J. M. Maclaren
Keyword(s):  
Transition Metal ◽  
Band Structure ◽  
Ground State ◽  
Fermi Energy ◽  
Band Structure Calculations ◽  
Spin Polarized ◽  
Densities Of States ◽  
Ferromagnetic Ground State ◽  
Sandwich Configuration ◽  
Structure Calculations

AbstractUsing ab-initio spin-polarized layer Korringa-Kohn-Rostoker (LKKR) band structure calculations, we investigated the possibility of having a stable ferromagnetic ground state in 4d transition metal (TM)–Ag(001) sandwiches (TM = Tc, Ru, Rh, and Pd). In contrast to recent calculations performed on systems with TM overlayers on Ag (001), we find that the TM sandwich configuration gives a paramagnetic ground state. While excellent agreement in general is obtained for the layer-projected densities of states (LDOS), the sandwich configuration lowers the densities of states at the Fermi energy (EF) in the case of Rh and Ru by a small amount which seemingly prevents the marginal ferromagnetic instability predicted by Eriksson et. al. (Phys. Rev. Lett. 66, 1350 (1991)) from occurring.

scholarly journals Equation of state of condensed matter in laser-induced high-pressure regime

2003 ◽  
Vol 21 (4) ◽  
pp. 523-528 ◽  
Author(s):  
B.K. GODWAL ◽  
R.S. RAO ◽  
A.K. VERMA ◽  
M. SHUKLA ◽  
H.C. PANT ◽  
...  
Keyword(s):  
Band Structure ◽  
Condensed Matter ◽  
Ambient Pressure ◽  
Band Structure Calculations ◽  
Temperature Isotherm ◽  
Shock Hugoniot ◽  
Total Energies ◽  
Pressure Regime ◽  
Structure Calculations ◽  
Good Agreement

We have simulated the shock Hugoniot of copper and uranium based on the results of first principles electronic structure calculations. The room temperature isotherm has been obtained by evaluating the accurate ground state total energies at various compressions, and the thermal and electronic excitation contributions were obtained by adopting isotropic models using the results obtained by the band structure calculations. Our calculations ensure smooth consideration of pressure ionization effects as the relevant core states are treated in the semi-core form at the ambient pressure. The pressure variation of the electronic Grüneisen parameter was estimated for copper using the band structure results, which leads to good agreement of the simulated shock Hugoniot with the measured shock data. The simulation results obtained for U are also compared with the experimental data available in literature and with our own data.

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