THE THERMOELECTRIC POWER OF V3X COMPOUNDS

1963 ◽  
Vol 41 (10) ◽  
pp. 1542-1546 ◽  
Author(s):  
M. P. Sarachik ◽  
G. E. Smith ◽  
J. H. Wernick
Keyword(s):  
Thermoelectric Power ◽  
Intermetallic Compounds ◽  
Conduction Band ◽  
Room Temperature ◽  
Band Model ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
Increasing Functions ◽  
Two Band Model

The thermoelectric powers of the intermetallic compounds V3Ge, V3Si, V3Ga, and V3Sn have been measured from their superconducting transition temperatures to room temperature. It is found that the thermoelectric coefficients are all positive and about 10 μv/° K at room temperature. The coefficients for V3Si, V3Ga, and V3Sn are monotonically increasing functions of the temperature, whereas for V3Ge there is a pronounced maximum at about 60° K. The results are discussed in terms of a two-band model consisting of a conduction band and a d-band.

Thermoelectric Power of the Liquid Sn—Te Alloy

1982 ◽  
Vol 37 (10) ◽  
pp. 1127-1131 ◽  
Author(s):  
D. H. Kurlat ◽  
M. Rosen
Keyword(s):  
Thermoelectric Power ◽  
Hard Sphere ◽  
Stoichiometric Composition ◽  
Band Model ◽  
Liquid Alloys ◽  
Sphere Approximation ◽  
The Difference ◽  
Predicted Values ◽  
Experimental Values ◽  
Two Band Model

The Seebeck coefficient (S) of Sni1-x- Tex liquid alloys was measured as a function of concentration and temperature. For 0 ≦ x <0.45 the behaviour is metallic; S values are small and negative, rising linearly with temperature. The predicted values of Ziman's theory when using the hard sphere approximation disagree with the experimental ones. The change in sign occurs for 0.45. For x = 0.5 (stoichiometric composition) the thermoelectric power decreases linearly with temperature. This fact is explained assuming a two-band model. For x ≧ 0.6 the liquid alloy becomes more semiconducting and presents a maximum in the isotherms of S for x = 0.65. For the excess tellurium concentration range we have calculated the difference EF - EV and γ/kB, assuming a S(1/T) law. The experimental values are compared with those of Dancy and Glazov.

The Electrical Resistivity, Thermal Conductivity, and Thermoelectric Power of Calcium from 30 K to 300 K

1975 ◽  
Vol 53 (5) ◽  
pp. 486-497 ◽  
Author(s):  
J. G. Cook ◽  
M. J. Laubitz ◽  
M. P. Van der Meer
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Band Structure ◽  
Large Deviations ◽  
Transport Properties ◽  
Thermoelectric Power ◽  
Band Model ◽  
Residual Resistance ◽  
Two Samples ◽  
Two Band Model

Data are presented for the thermal and electrical resistivity and thermoelectric power of two samples of Ca (having residual resistance ratios of 10 and 70) between 30 and 300 K. Large deviations from both Matthiessen's rule and the Wiedemann–Franz relationship are observed. The former are tentatively attributed to the presence of two distinct groups of carriers in Ca, and analyzed using the two band model. The latter deviations are interpreted as the effects of band structure. The thermoelectric power of Ca is large. In many respects the transport properties of Ca appear to be similar to those of the transition metals.

Transmission spectra of silver intercalated 2H-TaS2 and 1T-TiS2

1983 ◽  
Vol 61 (7) ◽  
pp. 965-970 ◽  
Author(s):  
G. A. Scholz ◽  
R. F. Frindt
Keyword(s):  
Charge Transfer ◽  
Energy Range ◽  
Conduction Band ◽  
Room Temperature ◽  
Direct Method ◽  
Silver Ions ◽  
Silver Cation ◽  
Band Model ◽  
Transmission Spectra ◽  
A Direct Method

The room temperature transmission spectra of Agx TaS2 and Agx TiS2 have been measured in the energy range from about 1.3 to 2.8 eV for various values of x. A rigid band model, where charge transfer from the silver cation to the lowest d conduction band of the host macro-anion occurs, can explain the changes in the spectra. These changes in the transmission spectra provide a direct method for monitoring staging and the intercalation rate of the silver ions.

Electron transport and conduction band structure of GaSb

1981 ◽  
Vol 59 (12) ◽  
pp. 1844-1850 ◽  
Author(s):  
Hyung Jae Lee ◽  
John C. Woolley
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electrical Conductivity ◽  
Conduction Band ◽  
Room Temperature ◽  
Energy Gap ◽  
Band Model ◽  
Scattering Coefficients ◽  
Wide Range ◽  
Different Temperatures

Calculations have been made using the Fletcher and Butcher method in a three conduction band model to fit a wide range of experimental transport data for n-type samples of GaSb: viz. Hall coefficient and electrical conductivity as a function of temperature and as a function of pressure at room temperature, magnetoresistance as a function of magnetic field at different temperatures, and Nernst–Ettingshausen coefficients as a function of magnetic field. Various energy gap parameters and scattering coefficients have been taken as adjustable and values determined for these which give good fits to all of the experimental data. Values of mobility for each of the Γ, L, and X bands have then been calculated as a function of temperature.

Te Substitution Effect in Low-Dimensional Superconductor NbSe2-xTex (x = 0, 0.1, 0.2)

2007 ◽  
Vol 546-549 ◽  
pp. 2019-2022 ◽  
Author(s):  
Ejaz Ahmed ◽  
Lin Jun Li ◽  
Cheng He ◽  
Hong Tao Wang ◽  
Jing Qin Shen ◽  
...  
Keyword(s):  
Upper Critical Field ◽  
Sharp Decrease ◽  
Substitution Effect ◽  
Vapor Transport ◽  
Band Model ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Low Dimensional ◽  
Two Band Model ◽  
Transport Method

The Te doped NbSe2-xTex (x=0, 0.10, 0.20) single crystals were prepared by vapor transport method and the variations of structure and superconducting properties with Te content were studied. It is found that the Te substitution increases the degree of disorder and causes sharp decrease of superconducting transition temperature (Tc). The temperature dependence of upper critical field (Hc2) of pure NbSe2 crystal can be fitted by the two-band model, and the effect of Te substitution on Hc2(T) is discussed.

STRUCTURAL INSTABILITY IN A Bi–Sr–Ca–Cu–O SYSTEM

1989 ◽  
Vol 03 (16) ◽  
pp. 1241-1246 ◽  
Author(s):  
XIAOHUA CHEN ◽  
HUIMIN SHEN ◽  
YENING WANG
Keyword(s):  
Phase Transition ◽  
Elastic Modulus ◽  
Internal Friction ◽  
Room Temperature ◽  
Structural Instability ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elastic Softening

Measurements of internal friction and elastic modulus on Bi–Sr–Ca–Cu–O system reveal that a certain kind of phase transition take place a few tens degrees higher than T c . X-ray diffraction measurements show that the symmetry remains unchanged from room temperature to 77 K but the lattice parameters jump at the transition temperatures. Ferroelastic loop were measured around the temperatures mentioned above, which indicates the existence of movable boundaries and elastic softening. It is considered that the instability favor the superconducting transition followed.

Investigation of the valence band structure of PbSe by optical and transport measurement

2013 ◽  
Vol 1490 ◽  
pp. 75-81 ◽  
Author(s):  
Thomas C. Chasapis ◽  
Yeseul Lee ◽  
Georgios S. Polymeris ◽  
Eleni C. Stefanaki ◽  
Euripides Hatzikraniotis ◽  
...  
Keyword(s):  
Band Structure ◽  
Valence Band ◽  
Room Temperature ◽  
Heavy Hole ◽  
Light Hole ◽  
Band Model ◽  
Valence Band Structure ◽  
Effective Masses ◽  
Wide Range ◽  
Two Band Model

ABSTRACTWe investigated the valence band structure of PbSe by a combined study of the optical and transport properties of p-type Pb1-xNaxSe, with Na concentrations ranging from 0 – 4%, yielding carrier densities in a wide range of 1018 – 1020 cm−3. Room temperature infrared reflectivity studies showed that the susceptibility (or conductivity) effective mass m* increases from ∼ 0.06mo to ∼ 0.5mo on increasing Na content from 0.08% to 3%. The Seebeck coefficient scales with doping in the whole temperature range, yielding lower values for higher Na contents, while the Hall coefficient increases on heating from room temperature showing a peak close to 650 K. The room temperature Pisarenko plot is well described by the simple parabolic band model up to ∼ 1·1020 cm−3. In order to describe the behaviour in the whole concentration range, the application of the two band model, i.e. light hole and heavy hole, was used giving density of states effective masses 0.28mo and 2.5mo for the two bands respectively.

High-Temperature Transport Properties of Palladium

1972 ◽  
Vol 50 (3) ◽  
pp. 196-205 ◽  
Author(s):  
M. J. Laubitz ◽  
T. Matsumura
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Large Deviations ◽  
Thermoelectric Power ◽  
The Other ◽  
Band Model ◽  
Experimental Systems ◽  
Two Band Model ◽  
Pure Palladium

The thermal conductivity, electrical resistivity, and absolute thermoelectric power of pure palladium have been determined from 90 to 1300 K in two experimental systems of proven reliability. These properties are compared with the sparse available literature data, and show large deviations from them, particularly for the thermal conductivity at high temperatures. The results are also analyzed in terms of a simple two-band model, where one band contains the carriers, and the other acts as a trap into which phonons scatter the carriers. When the recent density of states values of Mueller et al. are used, the model predicts correctly the temperature variation of the electrical resistivity, and reasonably well its observed magnitude and the observed Wiedemann–Franz ratio. However, the model fails badly in respect to the absolute thermoelectric power, predicting values twice as large as the observed ones. Modifications to the model are suggested which may improve the fit between the predicted and observed values.

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