Electronic Properties and Formation Mechanism of Metallo-Carbohedrenes

1994 ◽  
Vol 349 ◽  
Author(s):  
Yoshiyuki Kawazoe ◽  
Bing-Lin Gu ◽  
Mark van Schilfgaarde ◽  
Jing-Zhi Yu ◽  
Kaoru Ohno
Keyword(s):  
Electronic Properties ◽  
Density Of States ◽  
Density Functional ◽  
Local Density ◽  
Full Potential ◽  
Mulliken Population ◽  
Calculated Density ◽  
Single Cage ◽  
Atomic Orbitals ◽  
Local Density Functional

ABSTRACTWe have calculated the structure and electronic properties of several metallo-carbohedrenes within the local density-functional approximation, using both methods of a linear combination of atomic orbitals and full-potential muffin-tin orbitals. The calculated density of states and Mulliken population of double cage Ti14C21 and triple cage Ti18C29 are quite similar to that of single cage Ti8C12. There is no additional cohesion in multicage structure, which may explain why there is not a strong tendency to form larger, multi-cage structures. A new stable structure for Ti8C12 is also proposed and structures Ti10C12+x (x=1, 2, 3, 4, 5) have also been discussed.

First Principles Based Study of Ground State and Electronic Properties of TmPb3 Intermetallic Compound

2016 ◽  
Vol 28 ◽  
pp. 43-46
Author(s):  
Gitanjali Pagare
Keyword(s):  
Intermetallic Compound ◽  
Bulk Modulus ◽  
Electronic Properties ◽  
Density Of States ◽  
Ground State ◽  
First Principles ◽  
Density Functional ◽  
Full Potential ◽  
Electronic Band ◽  
Calculated Density

The ground state behavior of rare earth intermetallic compound TmPb3, which crystallize in AuCu3 type structure, has been examined using first principles density functional theory based on full potential linearized augmented plane wave (FP-LAPW) method. Very few study on structural and electronic properties of TmPb3 compound has been available in the literature, which motivated us to perform the present study. The spin polarized calculations are carried out within the PBE-GGA and LSDA for the exchange correlation (XC) potential. Our calculated ground state properties such as lattice constant (a0), bulk modulus (B) and its pressure derivative (B’) are in good agreement with the experimental results. The value of bulk modulus of TmPb3 is found to be 44.32 GPa and 55.01GPa by PBE-GGA and LSDA respectively. The electronic band structure (BS) and density of states (DOS) verify the metallic nature of this compound. The calculated density of states at the fermi level is found to be 0.16 states/eV and 19.50 states/eV for spin-up and spin-down modes respectively. The magnetic moment of TmPb3 is found to be 0.95.

Ab Initio Investigation of Structural and Electronic Properties of ErPb3 in AB3 Structure

2016 ◽  
Vol 28 ◽  
pp. 39-42 ◽  
Author(s):  
Shubha Dubey ◽  
Gitanjali Pagare ◽  
Ekta Jain ◽  
Sankar P. Sanyal
Keyword(s):  
Bulk Modulus ◽  
Total Energy ◽  
Electronic Properties ◽  
Density Of States ◽  
Experimental Results ◽  
Energy Calculation ◽  
Present Calculation ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Calculated Density

The structural properties and electronic properties of the intermetallic compound ErPb3 which crystallize in AuCu3 type structure (AB3) are studied by means of first principles total energy calculation using full potential linearized plane wave method (FP-LAPW) within the generalized gradient approximation of Perdew, Burke and Ernzrhof (PBE) and local spin density approximation (LSDA) for the exchange correlation functional and including spin magnetic calculation. The total energy is computed as a function of volume and fitted to the Birch-Murnaghan equation of state. The ground state properties of this compound such as equilibrium lattice parameter (a0), bulk modulus (B), and its pressure derivative (B’) are calculated and compared with the available experimental results. We find good agreement with the other theoretical and experimental results. For the compounds, the values of lattice constants obtained by PBE-GGA overestimates and by LSDA underestimates the available experimental values for the same, which verifies the reliability of the present calculation. The value obtained for the bulk modulus is 50.63 GPa. The analysis of electronic properties is achieved by the calculation of the band structures and the density of states in both the spin up and spin down modes, which show a metallic character of ErPB3 due to zero band gap. The values of calculated density of states are found to be 0.36 eV/states and 11.46 eV/states in spin-up and spin-down mode respectively. The calculated magnetic moment (μm) of ErPb3 is 2.06.

First-Principles Geometry Optimization of Polysilane

1988 ◽  
Vol 141 ◽  
Author(s):  
John W. Mintmire
Keyword(s):  
Total Energy ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Minimum Energy ◽  
Geometry Optimization ◽  
Functional Approach ◽  
Energy Structure ◽  
Atomic Orbitals ◽  
Local Density Functional

AbstractA first-principles approach is reviewed for calculating the total energy of chain polymers using a linear combination of atomic orbitals local-density functional approach. The geometry for the all-trans conformation of polysilane is optimized by finding the minimum energy structure using this method.

STRUCTURAL PHASE TRANSITION, ELASTIC AND ELECTRONIC PROPERTIES OF CuXSe2(X = In, Ga) CHALCOPYRITE

2012 ◽  
Vol 19 (02) ◽  
pp. 1250021 ◽  
Author(s):  
T. BOUGUETAIA ◽  
B. ABIDRI ◽  
B. BENBAHI ◽  
D. RACHED ◽  
S. HIADSI ◽  
...  
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Local Density ◽  
Structural Phase ◽  
Theoretical Data ◽  
Young Modulus ◽  
Orbital Method ◽  
Full Potential ◽  
Direct Band

The structural, elastic and electronic properties of chalcopyrite compound CuInSe2 and CuGaSe2 have been investigated using the full-potential linearized muffin-tin orbital method (FP-LMTO) within the frame of density functional theory (DFT). In this approach, the local density approximation is used for the exchange-correlation potential using Perdew–Wang parametrization. The equilibrium lattice parameters, bulk modulus, transition pressure, elastic constants and their related parameters such as Poisson's ratio, Young modulus, shear modulus and Debye temperature were calculated and compared with available experimental and theoretical data. They are in reasonable agreement. In this paper the electronic properties are treated with GGA + U approach, which brings out the important role played by the d-state of noble metal (Cu) and give the correct nature of the energy band gap. Our obtained results show that both compounds exhibit semi-conductor behaviour with direct band gap.

Ab initio study of structural, mechanical, thermal and electronic properties of perovskites Sr(Li,Pd)H3

2016 ◽  
Vol 30 (04) ◽  
pp. 1650003 ◽  
Author(s):  
S. Benlamari ◽  
S. Amara Korba ◽  
S. Lakel ◽  
H. Meradji ◽  
S. Ghemid ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Electronic Properties ◽  
Elastic Constants ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Velocity Variation ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic Band

The structural, elastic, thermal and electronic properties of perovskite hydrides SrLiH3 and SrPdH3 have been investigated using the all-electron full-potential linear augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). For the exchange-correlation potential, local-density approximation (LDA) and generalized gradient approximation (GGA) have been used to calculate theoretical lattice parameters, bulk modulus, and its pressure derivative. The present results are in good agreement with available theoretical and experimental data. The three independent elastic constants [Formula: see text], [Formula: see text] and [Formula: see text] are also reported. From electronic band structure and density of states (DOSs), it is found that SrLiH3 is an insulator characterized by an indirect gap of 3.48 eV, while SrPdH3 is metallic with a calculated DOSs at Fermi energy of 0.745 states/eV-unit cell. Poisson’s ratio [Formula: see text], Young’s modulus (E), shear modulus (G), anisotropy factor (A), average sound velocities [Formula: see text] and density [Formula: see text] of these compounds are also estimated for the first time. The Debye temperature is deduced from the average sound velocity. Variation of elastic constants and bulk modulus of these compounds as a function of pressure is also reported. Pressure and thermal effects on some macroscopic properties are predicted using the quasi-harmonic Debye model.

scholarly journals Local density approximation description of electronic properties of wurtzite cadmium sulfide (w-CdS)

2011 ◽  
Vol 89 (3) ◽  
pp. 319-324 ◽  
Author(s):  
E. C. Ekuma ◽  
L. Franklin ◽  
G. L. Zhao ◽  
J. T. Wang ◽  
D. Bagayoko
Keyword(s):  
Cadmium Sulfide ◽  
Density Of States ◽  
Density Functional ◽  
Local Density ◽  
State Density ◽  
Electron Effective Mass ◽  
Calculated Density ◽  
Sham Equation ◽  
Direct Band ◽  
Ground State Density

We present calculated, electronic, and related properties of wurtzite cadmium sulfide (w-CdS). Our ab initio, nonrelativistic calculations employ a local density functional approximation (LDA) potential and the linear combination of atomic orbitals (LCAO). Following the Bagayoko, Zhao, and Williams (BZW) method, we solved self-consistently both the Kohn–Sham equation and the equation giving the ground-state density in terms of the wave functions of the occupied states. Our calculated, direct band gap of 2.47 eV at the Γ point is in excellent agreement with experiment. So are the calculated density of states and the electron effective mass. In particular, our results reproduce the peaks in the conduction band density of states, within experimental uncertainties.

Compton Scattering and Electronic Properties of Tungsten Ditelluride

2013 ◽  
Vol 209 ◽  
pp. 107-110 ◽  
Author(s):  
Gunjan Arora ◽  
B.L. Ahuja
Keyword(s):  
Density Functional Theory ◽  
Density Of States ◽  
Density Functional ◽  
Local Density ◽  
Measured Data ◽  
Compton Profile ◽  
Energy Bands ◽  
Functional Theory ◽  
Atomic Orbitals ◽  
Hartree Fock

We report the first ever isotropic experimental Compton profile of tungsten ditelluride using 20 Ci 137Cs Compton spectrometer. To compare our experimental data, we have also computed the Compton profiles, energy bands, density of states and band gap using Hartree-Fock and density functional theory within linear combination of atomic orbitals. The measured data is found to be in better accordance with the generalised gradient approximation of density functional theory than Hartree-Fock and local density approximation. We have discussed the nature of bonding in WTe2 using energy bands and density of states.

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