ON THE ELECTRONIC STRUCTURE OF CrO2: NEW EXPERIMENTS AND THEORY

1993 ◽  
Vol 07 (01n03) ◽  
pp. 345-348 ◽  
Author(s):  
H. BRÄNDLE ◽  
D. WELLER ◽  
J. C. SCOTT ◽  
J. STICHT ◽  
P. M. OPPENEER ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Energy Range ◽  
Ab Initio ◽  
Optical Conductivity ◽  
Optical Constants ◽  
Conductivity Tensor ◽  
Experimental Confirmation ◽  
Spin Polarized ◽  
Self Consistent ◽  
First Time

Spectroscopic investigations of the optical constants n and k and the magneto-optical polar Kerr effects θK and εK were used to deterimine the diagonal and off-diagonal conductivity tensor elements of CrO 2 in the energy range 0.8-5eV. The data can be readily explained on the basis of self-consistent spin-polarized bandstructure calculations. A direct comparison of the measured and calculated diagonal optical conductivity is presented for the first time, which can be viewed as experimental confirmation of the ab initio calculated bandstructure of CrO 2.

The Atomic and Electronic Structures of Grain Boundaries in Silicon-Carbide and Silicon

1990 ◽  
Vol 193 ◽  
Author(s):  
M. Kohyama ◽  
S. Kose ◽  
M. Kinoshita ◽  
R. Yamamoto
Keyword(s):  
Electronic Structure ◽  
Electronic Structures ◽  
Boundary Energy ◽  
Tight Binding ◽  
Atomic Model ◽  
Electrostatic Energy ◽  
Hrem Image ◽  
Self Consistent ◽  
First Time ◽  
Atomic And Electronic Structure

ABSTRACTThe atomic and electronic structure of the {122} Σ=9 grain boundary in cubic SiC has been calculated for the first time using the self-consistent tight-binding (SCTB) method. An atomic model consisting of zigzag arrangement of 5-membered and 7-membered rings similar to that in the same boundary in Si or Ge has been constructed from a HREM image, although Si-Si and C-C wrong bonds are repeated alternately at the interface in this model. We have also performed calculations of the same boundary in Si using the SCTB method for comparison, and have obtained the results similar to those previously obtained by other theoretical schemes. The calculated boundary energy in SiC has shown that the present atomic model can exist stably as compared with the two surfaces, and the calculated boundary electronic structure in SiC has no deep states in the gap as well as that in Si. However, it has been found that the the increase in the electrostatic energy caused by the wrong bonds is a large part of the present boundary energy in SiC differently from that in Si, and it has been shown that the wrong bonds introduce the wrong-bond localised states at the band edges and within the valence band.

AB-INITIO CALCULATIONS OF SUPERCONDUCTING PROPERTIES OF YBa2Cu3O7

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3579-3581 ◽  
Author(s):  
G. L. ZHAO ◽  
D. BAGAYOKO
Keyword(s):  
Electronic Structure ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
High Energy ◽  
Optical Phonons ◽  
Superconducting Properties ◽  
S Wave ◽  
Gap Equation ◽  
Self Consistent ◽  
Good Agreement

We present ab-initio calculations for the electronic structure and superconducting properties of YBa 2 Cu 3 O 7 (YBCO). The electronic structure was calculated using a self-consistent ab-initio LCAO method. We solved the anisotropic Eliashberg gap equation numerically. The strong coupling of the high energy optical phonons around 60-73 meV, with the electrons at the Fermi surface, leads to a high Tc in YBCO. The calculated Tc is about 89 K for μ*=0.1. The good agreement of the calculated results with experimental measurements and the ab-initio nature of the calculations support the scenario of an anisotropic s-wave superconductor for YBCO.

First-Principle Studies of Permanent-Magnet Materials

1999 ◽  
Vol 577 ◽  
Author(s):  
S.S. Jaswal ◽  
R.F. Sabiryanov
Keyword(s):  
Electronic Structure ◽  
Electronic Structure Calculations ◽  
First Principle ◽  
Rare Earth Compounds ◽  
Spin Polarized ◽  
Self Consistent ◽  
Hard Magnet ◽  
Permanent Magnet Materials ◽  
Structure Calculations ◽  
Curie Temperatures

ABSTRACTFirst-principle electronic structure studies complement experimental research on hard-magnet materials. Since the discovery of Nd 2Fel4B in 1984, the research in this area has been concentrated on T(Fe,Co)-rich rare-earth compounds such as RT12 and R2T17 and exchange coupled hard/soft phases. Self-consistent spin-polarized electronic structure calculations are carried out for the sequence YFc2→ YFe3→Y2Fe17→YFe12 to study the variation of the magnetization and Curie temperature as a function of the Fe concentration. Calculations are performed for R2T17 systems which show significant improvements in their Curie temperatures with interstitial and substitutional modifications. The calculated results are compared with the available experimental data. Computer simulations are carried out for FePt/Fe and SmCo5/Co1−x -Fex, hard/soft multilayers.

Tight-Binding Calculations of Complex Defects in Semiconductors: Comparison with AB Initio Results

1997 ◽  
Vol 491 ◽  
Author(s):  
M. Kohyama ◽  
N. Arai ◽  
S. Takeda
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Tight Binding ◽  
The Self ◽  
Planar Defects ◽  
Self Consistent ◽  
Tight Binding Method ◽  
Tilt Boundaries ◽  
Defects In Semiconductors

ABSTRACTComplex defects in Si and SiC such as coincidence tilt boundaries, planar defects and self-interstitial clusters were dealt with by using the transferable tight-binding method for Si and the self-consistent tight-binding method for SiC. These results have been compared with ab initio calculations of similar configurations. Essential features of the tight-binding results have been supported by the ab initio results. Especially, the agreement on stable atomic configurations is good, although there exits a tendency that energy increases are somewhat overestimated by the tight-binding methods. Serious faults have been found for the electronic structure by the tight-binding method for SiC.

Structural, elastic and thermo-electronic properties of paramagnetic perovskite PbTaO3

RSC Advances ◽  
2016 ◽  
Vol 6 (53) ◽  
pp. 48009-48015 ◽  
Author(s):  
Shakeel Ahmad Khandy ◽  
Dinesh C. Gupta
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Electronic Properties ◽  
Structural Stability ◽  
Density Functional ◽  
Functional Theory ◽  
Self Consistent ◽  
First Time

Self-consistent ab initio calculations with highly precise spin-polarised, density functional theory (DFT) have been performed for the first time, to study the structural stability, mechanical and magneto-electronic properties of cubic perovskite PbTaO3.

Ab initio study of water: self-consistent determination of electronic structure and liquid state properties

1997 ◽  
Vol 276 (1-2) ◽  
pp. 20-25 ◽  
Author(s):  
Sarah Maw ◽  
Hirofumi Sato ◽  
Seiichiro Ten-no ◽  
Fumio Hirata
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Liquid State ◽  
Ab Initio Study ◽  
Self Consistent
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