CRYSTAL STRUCTURE AND BAND GAP OF RUBIDIUM HYDRIDE TO 120 GPa

1995 ◽  
Vol 09 (18) ◽  
pp. 1133-1140 ◽  
Author(s):  
KOUROS GHANDEHARI ◽  
HUAN LUO ◽  
ARTHUR L. RUOFF ◽  
STEVEN S. TRAIL ◽  
FRANCIS J. DISALVO
Keyword(s):  
Crystal Structure ◽  
Equation Of State ◽  
Band Gap ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Measurements ◽  
B2 Phase ◽  
Gap Data

Energy dispersive x ray diffraction measurements were performed on RbH to 120 GPa. RbH was observed to transform from the B2 phase to the orthorhombic, CrB, phase at 85 GPa. The equation of state for the B2 phase and the CrB phase are reported. Transmission measurements were made to 120 GPa to determine the band gap versus pressure in RbH. We report here the first measurement of the band gap of RbH at zero pressure at 4.91 eV. At 120 GPa, the band gap closed to 2.68 eV. Extrapolating the present band gap data leads to a zero gap at about 310 GPa.

Structural and Electronic Properties of (CdTe)1−x(In2Te3)x Films Grown by Close-spaced vapor Transport Combined with Free Evaporation

2000 ◽  
Vol 15 (8) ◽  
pp. 1811-1815 ◽  
Author(s):  
M. Zapata-Torres ◽  
Y. P. Mascarenhas ◽  
M. A. Santana-Aranda ◽  
J. Luyo-Alvarado ◽  
M. Melé-Lirandez ◽  
...  
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Single Phase ◽  
Vapor Transport ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Structural And Electronic Properties ◽  
Direct Band ◽  
Transmission Measurements

The structural and electronic properties of (CdTe)1−x(In2Te3)x thin films as a function of substrate temperature were studied using x-ray diffraction, energy dispersive x-ray analysis, and Raman, transmission, and modulated transmission spectroscopies. The films were grown by the close-spaced vapor transport technique combined with free evaporation; CdTe and In2Te3 were used as sources. From x-ray diffraction the presence of mixed phases and differences in composition were detected, and good correlation with Raman spectroscopy was found. Transmission spectroscopy suggested the possibility of a modulation of the band gap of the alloy from a value as low as 0.5 eV up to 1.5 eV. Single-phase films presented a direct band gap of around 1.15 eV, as obtained from modulated transmission measurements.

Novel Structure of MgSe in the Multimegabar Regime: Positional Parameter Determination

1997 ◽  
Vol 499 ◽  
Author(s):  
Arthur L. Ruoff ◽  
Ting Li ◽  
Chandrabhas Narayana ◽  
Huan Luo ◽  
Raymond G. Greene
Keyword(s):  
Equation Of State ◽  
Structural Transformations ◽  
Energy Dispersive ◽  
Parameter Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Positional Parameter ◽  
Novel Structure ◽  
Diffraction Peaks ◽  
Intensity Calculation

ABSTRACTThe structural transformations in the II-VI compound MgSe have been studied under pressure using energy dispersive x-ray diffraction. MgSe transforms ‘continuously’ from the rocksalt (Bl) structure to a FeSi (B28) or Au-Be structure beginning at 99 ± 8 GPa. At 202 GPa, MgSe is approaching 7-fold coordination with u = 0.0828 and w = 0.4173. The method for intensity calculation of the diffraction peaks is presented. Using the Birch equation, the equation of state to 146 GPa was determined with Bo = 62.8 + 1.6 GPa and Bo′ = 4.1.

Synthesis and structure stability of Ba2CuO3+δ under high pressure

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542024 ◽  
Author(s):  
W. M. Li ◽  
Q. Q. Liu ◽  
Y. Liu ◽  
S. M. Feng ◽  
X. C. Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Equation Of State ◽  
Room Temperature ◽  
Text Structure ◽  
Structure Stability ◽  
Nominal Composition ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray

The [Formula: see text] sample with the nominal composition was synthesized. Powder X-ray diffraction (XRD) experiments confirm that it crystallizes in an orthorhombic structure with space group Immm. The synchrotron powder XRD results suggest that the crystal structure of [Formula: see text] keeps stable under pressure up to 34 GPa at room temperature with nearly isotropic compressibility. The equation of state for [Formula: see text] was obtained. The results offer opportunities to further synthesize and research [Formula: see text] superconductor with tetragonal [Formula: see text] structure.

Influence of the Ga Alloying on the Properties of NiAl Based Alloys

2007 ◽  
Vol 130 ◽  
pp. 117-120
Author(s):  
Yuri N. Koval ◽  
G.E. Monastyrsky ◽  
Valeri V. Odnosum ◽  
Tomasz Czeppe ◽  
R.Ya. Musienko ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Martensitic Transformation ◽  
Martensitic Phase ◽  
Coarse Grain ◽  
Martensitic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
B2 Phase

Influence of the Ga alloying on the crystal structure and parameters of the martensitic transformation are presented. X-ray diffraction has shown the multiphase composition of the samples (β (B2)- phase, γ′ (L12)-phase, (L10)-martensitic phase, Ni5Al3-phase). Metallographic investigations have demonstrated the coarse grain of B2 phase with non-regular needles of Ni3Al and typical martensitic structure. Ga did not suppress the martensitic transformation in NiAlGa alloys. The Ni to Al ratio and quantity of Ga determine the parameters of martensitic transformation.

scholarly journals Effect of Ag in CdSe thin films prepared using thermal evaporation

2017 ◽  
Vol 51 (12) ◽  
pp. 1656
Author(s):  
T.C.M. Santhosh ◽  
Kasturi V. Bangera ◽  
G.K. Shivakumar
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Thermal Evaporation ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Potential Applications ◽  
Evaporation Technique ◽  
Transmission Measurements

It has been a general practice to dope thin films with suitable dopants to modify the properties of the films to make them more suitable for potential applications. When the dopant concentrations are low, they do not normally affect the structure and morphology of the films. However, it may lead to drastic changes in electronic properties of the films. This might result from the dopant getting incorporated into the lattice of the material of the films. Cadmium selenide is an important compound semiconductor material with an attractive energy band gap. The present work relates to an attempt made to dope CdSe thin films with silver. CdSe : Ag (1 to 5%) thin films were deposited on glass substrates at an optimized substrate temperature of 453 K using thermal evaporation technique. The grown films were analyzed using X-ray diffraction, scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDX) techniques. It is observed that undoped CdSe thin films and CdSe : Ag films have hexagonal structure. The grain size was found to increase marginally with an increase in the Ag concentration. The optical band gap of the films determined by optical transmission measurements agree with that of CdSe. Electrical conductivity is observed to increase from 10-4 to 3.66 (Omega ·cm)-1 on addition of silver. The variation of resistance with temperature indicates that the prepared films consist of CdSe and Ag existing as two separate phases coexisting and contributing individually to the resistivity of the films. DOI: 10.21883/FTP.2017.12.45181.8430

SYNTHESIS AND STRUCTURAL STABILITY OF BiRhO3 AT HIGH PRESSURE

2013 ◽  
Vol 27 (15) ◽  
pp. 1362021 ◽  
Author(s):  
X. LI ◽  
Q. Q. LIU ◽  
W. HAN ◽  
Y. LIU ◽  
X. D. LI ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Equation Of State ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Spin Orbital ◽  
X Ray ◽  
Spin Orbital Coupling ◽  
Strong Spin

The bismuth rhodate BiRhO 3, which crystallizes in a perovskite structure, was synthesized under high-pressure and high-temperature conditions, using a 6–8 double stage multi-anvil apparatus. The synchrotron powder X-ray diffraction data suggest that the crystal structure of the BiRhO 3 perovskite is stable under pressures up to 34 GPa at room temperature with anisotropic compressibility. The equation of state for BiRhO 3 compound was obtained. The results offer opportunities for further research into the BiRhO 3 quantum compound with strong spin orbital coupling.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

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