Conduction bands of GaSb

1969 ◽  
Vol 47 (3) ◽  
pp. 241-247 ◽  
Author(s):  
Eric H. van Tongerloo ◽  
John C. Woolley
Keyword(s):  
Single Crystal ◽  
Faraday Rotation ◽  
Room Temperature ◽  
Free Carrier ◽  
Temperature Data ◽  
Energy Separation ◽  
Mass Ratio ◽  
Scattering Parameter ◽  
Conduction Bands ◽  
Effective Mass Ratio

Room temperature measurements of free-carrier Faraday rotation have been made on four different single-crystal n-type tellurium-doped samples of GaSb which had been used previously in magnetoresistance measurements. From the combined results for each specimen, values have been calculated for the energy separation of the (000) and [Formula: see text] conduction band minima, ΔE, and the transverse effective-mass ratio of the [Formula: see text] electrons, m1t/m. It is found that ΔE is a function of tellurium content. The value of ΔE at 4.2 °K for an intrinsic sample is hence found to be 0.078 eV. The values obtained for m1t/m, the variation of ΔE with tellurium content (dΔE/dy), and the temperature coefficient of ΔE (dΔE/dT) depend upon the value of the scattering parameter s assumed in the analysis of the room-temperature data. It is shown that the correct value of s lies in the range 0.5 to 1.0 and this gives values for m1t/m = 0.110 and dΔEdy = 0.50 eV/atomic % Te, while dΔE/dT probably lies in the range 0 to −2 × 10−5 eV/°K.

scholarly journals Crystal structure of apatite type Ca2.49Nd7.51(SiO4)6O1.75

2016 ◽  
Vol 72 (2) ◽  
pp. 209-211 ◽  
Author(s):  
Thu Hoai Le ◽  
Neil R. Brooks ◽  
Koen Binnemans ◽  
Bart Blanpain ◽  
Muxing Guo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Room Temperature ◽  
Solubility Limit ◽  
Temperature Data ◽  
X Ray Diffraction ◽  
Slow Cooling ◽  
X Ray ◽  
Natural Apatite ◽  
Apatite Type

The title compound, Ca2+xNd8–x(SiO4)6O2–0.5x(x= 0.49), was synthesized at 1873 K and rapidly quenched to room temperature. Its structure has been determined using single-crystal X-ray diffraction and compared with results reported using neutron and X-ray powder diffraction from samples prepared by slow cooling. The single-crystal structure from room temperature data was found to belong to the space groupP63/mand has the composition Ca2.49Nd7.51(SiO4)6O1.75[dicalcium octaneodymium hexakis(orthosilicate) dioxide], being isotypic with natural apatite and the previously reported Ca2Nd8(SiO4)6O2and Ca2.2Nd7.8(SiO4)6O1.9. The solubility limit of calcium in the equilibrium state at 1873 K was found to occur at a composition of Ca2+xNd8–x(SiO4)6O2–0.5x, wherex= 0.49.

The conduction bands in 6H and 15R silicon carbide I. Hall effect and infrared Faraday rotation measurements

1967 ◽  
Vol 299 (1458) ◽  
pp. 383-392 ◽  
Keyword(s):  
Silicon Carbide ◽  
Hall Effect ◽  
Faraday Rotation ◽  
Hall Coefficient ◽  
Experimental Error ◽  
Room Temperature ◽  
Symmetry Axis ◽  
Conduction Bands ◽  
Axis Of Symmetry ◽  
Made In

Measurements of infrared Faraday rotation and Hall Effect have been made in a number of specimens belonging to the 6H and 15H polytypes of silicon carbide. Within experimental error the Hall coefficient in these samples was found to be isotropic and it is concluded that the conduction band extrema in both polytypes are most probably located on the symmetry axis. For this model the Faraday rotation results give the effective mass appropriate to directions perpendicular to the axis of symmetry as 0.25±0.02 m 0 in the 6H polytype and 0.28 ± 0.02 m 0 in the 15R polytype. Considerable care was required to ensure that the specimens used were uniform in carrier concentration and free from serious crystallographic faults; the precautions taken to meet these requirements and in particular the avoidance of one frequently occurring crystallographic imperfection are described in some detail. All the measurements were made at room temperature.

Electron scattering in InAsxSb1−x alloys

1968 ◽  
Vol 46 (10) ◽  
pp. 1191-1198 ◽  
Author(s):  
Marcel J. Aubin ◽  
John C. Woolley
Keyword(s):  
Magnetic Field ◽  
Electron Scattering ◽  
Faraday Rotation ◽  
Hall Coefficient ◽  
Fermi Energy ◽  
Room Temperature ◽  
Zero Field ◽  
Scattering Mechanism ◽  
Scattering Parameter ◽  
The Magnetic Field

Room-temperature measurements of the thermoelectric power α and Hall coefficient R have been made as a function of the magnetic field B on polycrystalline n-type samples of InAsxSb1−x, alloys of carrier concentration ~1017/cm3. Hence saturation values α∞ and R∞ and zero-field values α∞ and R∞ have been determined. Using these values of α∞ and α∞ and assuming a Kane model for the conduction band, values have been determined for the Fermi energy EF and the scattering parameter s over the whole alloy range. In all cases, the value of s is close to 0.5, indicating that the dominant scattering mechanism in the alloys is piezoelectric scattering. From the EF and R∞ data, values of the bottom of the band effective mass have been calculated and these are compared with similar values obtained from Faraday rotation results.

Free-carrier Faraday rotation in InAsxSb1−x alloys

1968 ◽  
Vol 46 (10) ◽  
pp. 1199-1206 ◽  
Author(s):  
Eric H. van Tongerloo ◽  
John C. Woolley
Keyword(s):  
Matrix Element ◽  
Carrier Concentration ◽  
Faraday Rotation ◽  
Hall Coefficient ◽  
Room Temperature ◽  
Calculated Data ◽  
Free Carrier ◽  
Similar Data ◽  
The Matrix ◽  
Power Measurements

Room-temperature free-carrier Faraday rotation measurements in the wavelength range 6–25 μ and Hall-coefficient measurements have been made on polycrystalline n-type samples of InAsxSb1−x alloys of carrier concentration ~1017/cm3. Using these data and a Kane equation for the conduction band, values of the bottom of the band effective mass m0* have been determined over the whole alloy range. The results are compared with similar data from magnetothermoelectric power measurements and also with previously calculated data. From the m0* results, values of the square of the matrix element P2 have been calculated as a function of x.

scholarly journals Raman Spectrum of Rubidium Thiocyanate at 37 K and Room Temperature

1989 ◽  
Vol 42 (4) ◽  
pp. 389 ◽  
Author(s):  
MJ Joyce ◽  
F Ninio
Keyword(s):  
Raman Spectrum ◽  
Low Temperature ◽  
Single Crystal ◽  
Room Temperature ◽  
Temperature Data ◽  
Phonon Modes ◽  
New Classification ◽  
External Mode ◽  
Recent Interpretation

The single crystal Raman spectrum of RbSCN from 0 to 2200 cm-l was studied between 37 K and room temperature. A new eak was observed in the B2g polarisation and is believed to be an external mode. The low temperature data indicate that previous interpretations of the external modes are in error. A new classification of these modes is given. Further, whereas the internal modes are in agreement with previous studies, some multi phonon modes are not. The assumed isomorphism between bSCN and KSCN suggests a correction to the most recent interpretation of the spectrum

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

scholarly journals Old Donors for New Molecular Conductors: Combining TMTSF and BEDT-TTF with Anionic (TaF6)1−x/(PF6)x Alloys

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 386
Author(s):  
Magali Allain ◽  
Cécile Mézière ◽  
Pascale Auban-Senzier ◽  
Narcis Avarvari
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Density Wave ◽  
Spin Density Wave ◽  
Orthorhombic Phase ◽  
Molecular Conductors ◽  
Bechgaard Salts ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Resistivity Measurements

Tetramethyl-tetraselenafulvalene (TMTSF) and bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) are flagship precursors in the field of molecular (super)conductors. The electrocrystallization of these donors in the presence of (n-Bu4N)TaF6 or mixtures of (n-Bu4N)TaF6 and (n-Bu4N)PF6 provided Bechgaard salts formulated as (TMTSF)2(TaF6)0.84(PF6)0.16, (TMTSF)2(TaF6)0.56(PF6)0.44, (TMTSF)2(TaF6)0.44(PF6)0.56 and (TMTSF)2(TaF6)0.12(PF6)0.88, together with the monoclinic and orthorhombic phases δm-(BEDT-TTF)2(TaF6)0.94(PF6)0.06 and δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57, respectively. The use of BEDT-TTF and a mixture of (n-Bu4N)TaF6/TaF5 afforded the 1:1 phase (BEDT-TTF)2(TaF6)2·CH2Cl2. The precise Ta/P ratio in the alloys has been determined by an accurate single crystal X-ray data analysis and was corroborated with solution 19F NMR measurements. In the previously unknown crystalline phase (BEDT-TTF)2(TaF6)2·CH2Cl2 the donors organize in dimers interacting laterally yet no organic-inorganic segregation is observed. Single crystal resistivity measurements on the TMTSF based materials show typical behavior of the Bechgaard phases with room temperature conductivity σ ≈ 100 S/cm and localization below 12 K indicative of a spin density wave transition. The orthorhombic phase δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57 is semiconducting with the room temperature conductivity estimated to be σ ≈ 0.16–0.5 S/cm while the compound (BEDT-TTF)2(TaF6)2·CH2Cl2 is also a semiconductor, yet with a much lower room temperature conductivity value of 0.001 to 0.0025 S/cm, in agreement with the +1 oxidation state and strong dimerization of the donors.

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