scholarly journals Stability and the Electronic Structure of XB2 (X = Pt, Ir, Pd, Rh, Os) Diborides

2017 ◽  
Vol 54 (4) ◽  
pp. 49-57
Author(s):  
A.I. Popoola ◽  
A.Y. Odusote ◽  
O.E. Ayo-Ojo
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Platinum Group Metal ◽  
First Principle ◽  
Boron Addition ◽  
Superhard Materials ◽  
Electronic Density ◽  
First Principle Calculations ◽  
Structural And Electronic Properties ◽  
Metal Diborides

AbstractFirst-principle calculations have been performed to investigate the structural and electronic properties of platinum group metal diborides in the stoichiometry XB2(X = Pt, Ir, Pd, Rh, Os). All investigated compounds have shown to belong to the orthorhombicPmmn space group rather than theC2/m previously predicted in some of the compositions. Compressibility will reduce with boron addition in Pt, Pd and Rh, but will increase with boron addition into Ir and Os. The electronic density of states show that all the compounds are metals, with PtB2, PdB2and OsB2being potentially incompressible and superhard materials.

First-principle investigation of electronic structure and mechanical properties of AlMgB14

2009 ◽  
Vol 1224 ◽  
Author(s):  
Liwen F Wan ◽  
Scott P Beckman
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Ab Initio ◽  
Density Of States ◽  
Fermi Energy ◽  
First Principle ◽  
Metal Atoms ◽  
Structural And Electronic Properties ◽  
The Impact ◽  
Atomic And Electronic Structure

AbstractThe structural and electronic properties of AlMgB14 are investigated using ab initio methods. The impact of vacancies and electron doping on the crystal’s atomic and electronic structure is investigated. It is found that removing metal atoms does not influence the density of states, except for changes to the Fermi energy. The density of states of the off-stoichiometric Al0.75Mg0.75B14 crystal and the AlMgB14 crystal with five electrons removed are nearly identical. The removal of six electrons results in an 11% contraction in the crystal’s volume. This is associate with the removal of electrons from the B atoms’ 2p-states.

PRESSURE EFFECT ON THE MgB2 ELECTRON STRUCTURE FROM FIRST PRINCIPLE CALCULATIONS

2007 ◽  
Vol 21 (16) ◽  
pp. 2793-2803
Author(s):  
LI CHEN
Keyword(s):  
Electronic Structure ◽  
Fermi Level ◽  
Density Of States ◽  
Electron Distribution ◽  
Pressure Effect ◽  
The Other ◽  
First Principle ◽  
First Principle Calculations ◽  
Bonding Property ◽  
Density Population

The electronic structure of MgB 2 with different lattice parameters, which represents the influence of pressure, has been studied from HF calculation. It has been found that the density of states at the Fermi level decreases with the decrease in lattice constant, which implies that the pressure can reduce the superconductivity of MgB 2. It was also found that more electrons are introduced from the Mg layer to the B layer with increasing pressure, resulting in the number of holes on the B layer being reduced, thus reducing superconductivity. The electron density population at different pressures clearly shows that the triangle-shaped electron distribution in the B plane, extended along the B–B bonds, indicates the typical sp2 orbitals. On the other hand, there is no covalency feature between Mg and B atoms, indicating the ionic bonding property between Mg and B layers.

Nano-domains in thermoelectric Half-Heusler CoTi0.5Sc0.5Sb alloys

2015 ◽  
Vol 1735 ◽  
Author(s):  
Joaquin Miranda Mena ◽  
Heiko G. Schoberth ◽  
Thomas Gruhn ◽  
Heike Emmerich
Keyword(s):  
Phase Separation ◽  
Density Of States ◽  
Figure Of Merit ◽  
Functional Materials ◽  
First Principle ◽  
Electronic Density ◽  
Configurational Energy ◽  
First Principle Calculations ◽  
Great Relevance ◽  
Lattice Heat

ABSTRACTNano-phase separation is of great relevance for functional materials like thermoelectrics. Indeed, nano-domains in CoSb-based half-Heusler thermoelectrics have been found to reduce the lattice heat conductivity, which increases the figure of merit. Within this context, we studied the configurational energy in the alloy CoTi0.5Sc0.5Sb by means of first-principle calculations. We consider structures formed by Ti (Sc) nano-domains. In recent publications we have showed that these domains are the most stable atomic configurations. In this work we found that for a given concentration the electronic density of states is considerably modified as the volume of the domains are increased.

Dependence of the Second-order G'-band Profile on the Electronic Structure of Single-wal Nanotubes

2001 ◽  
Vol 706 ◽  
Author(s):  
A. G. Souza Filho ◽  
A. Joribo ◽  
G. Dresselhaus ◽  
M. S. Dresselhaus ◽  
A. K. Swan ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Raman Spectra ◽  
Density Of States ◽  
Resonance Raman ◽  
Second Order ◽  
Electronic Density ◽  
Van Hove Singularities ◽  
Band Profile ◽  
Resonance Raman Spectra

AbstractWe analyze the dependence of the second-order G'-band profile in terms of their (n,m) indices by measuring the resonance Raman spectra of several semiconducting and metalic isolated single wal carbon nanotubes. We show that this profile is very sensitive to the electronic structure, thus making it possible to get structural (n,m) information and to probe the splitting of the van Hove singularities in the electronic density of states due to the trigona warping effect.

scholarly journals Unexpected bowing band evolution in an all-inorganic CsSn1−xPbxBr3 perovskite

RSC Advances ◽  
2020 ◽  
Vol 10 (44) ◽  
pp. 26407-26413
Author(s):  
Yufan Xia ◽  
Yuxuan Chen ◽  
Tian Luo ◽  
Hongyao Liang ◽  
Yujia Gao ◽  
...  
Keyword(s):  
Electronic Properties ◽  
First Principle ◽  
Inorganic Perovskite ◽  
First Principle Calculations ◽  
Structural And Electronic Properties

We theoretically investigated the structural and electronic properties of the all-inorganic perovskite CsSn1−xPbxBr3, compared with the mixed perovskite compound MAyCs1−ySn1−xPbxBr3, based on first-principle calculations.

Electronic structure and optical properties of Fe-doped SnS2 from first-principle calculations

RSC Advances ◽  
2016 ◽  
Vol 6 (5) ◽  
pp. 3480-3486 ◽  
Author(s):  
Lili Sun ◽  
Wei Zhou ◽  
Yanyu Liu ◽  
Dandan Yu ◽  
Yinghua Liang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Infrared Region ◽  
First Principle ◽  
Fe Doping ◽  
Visible Absorption ◽  
First Principle Calculations

The Fe doping can increase the visible absorption of SnS2 and extend the absorption into the infrared region.

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