Thermoelectric power ofBi2−xPbxCa2Sr2Cu3O10based on the two-band model

1994 ◽  
Vol 49 (9) ◽  
pp. 6385-6387 ◽  
Author(s):  
V. P. S. Awana ◽  
V. N. Moorthy ◽  
A. V. Narlikar
Keyword(s):  
Thermoelectric Power ◽  
Band Model ◽  
Two Band Model

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.

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.

Transport Properties of NbSe2

1974 ◽  
Vol 52 (10) ◽  
pp. 861-867 ◽  
Author(s):  
D. J. Huntley ◽  
R. F. Frindt
Keyword(s):  
Large Deviations ◽  
Phase Change ◽  
Temperature Dependence ◽  
Transport Properties ◽  
Thermoelectric Power ◽  
Hall Coefficient ◽  
Band Model ◽  
Crystal Orientations ◽  
Two Band Model

The Hall coefficient, magnetoresistance, and thermoelectric power of several specimens of NbSe2 have been measured as a function of temperature for various crystal orientations. A range of behaviour of the Hall coefficient has been observed varying from a reversal at 27 K for the purest specimen to no temperature dependence for the most impure. The magnetoresistance shows large deviations from Kohler's rule which are correlated with the Hall reversal. The results are discussed in terms of a possible phase change or a two-band model.

Magnetic Field Dependence of the Thermoelectric Power of Iron

1972 ◽  
Vol 50 (22) ◽  
pp. 2836-2839 ◽  
Author(s):  
F. J. Blatt
Keyword(s):  
Magnetic Field ◽  
Thermoelectric Power ◽  
Magnetic Field Dependence ◽  
Cold Work ◽  
Transverse Magnetic ◽  
Band Model ◽  
Spin Orbit Coupling ◽  
Phonon Drag ◽  
Domain Alignment ◽  
Two Band Model

The thermoelectric power of iron exhibits a broad maximum of about 17 µV/K near 200 K. The relatively high temperature of this maxim and its dependence on alloying and cold work argue against phonon drag as the mechanism responsible for this peak. Recently, MacInnes and Schröder proposed that this peak derives from anisotropic (scew) scattering due to spin–orbit coupling, which may be simulated by a large effective transverse magnetic field. Their calculations, which reproduce experimental observations quite well, are based on an expression derived by Sondheimer that is valid for an ideal two-band model. According to this model and the suggestion of MacInnes and Schröder, the thermoèlectric power of iron should be strongly influenced by domain alignment. Measurements of the dependence of the thermoelectric power of iron in transverse and longitudinal magnetic fields reported here yield results contrary to the predictions of that model.

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.

IONIZATION ENERGY AND IMPURITY BAND CONDUCTION OF SHALLOW DONORS IN n-GALLIUM ARSENIDE

1967 ◽  
Vol 45 (1) ◽  
pp. 119-126 ◽  
Author(s):  
J. Basinski ◽  
R. Olivier
Keyword(s):  
Ionization Energy ◽  
Impurity Band ◽  
Shallow Donor ◽  
Band Model ◽  
A Value ◽  
Transition Concentration ◽  
Temperature Electron ◽  
Two Band Model ◽  
Band Conduction ◽  
Made In

Hall effect and resistivity measurements have been made in the temperature range 4.2–360 °K on several samples of n-type GaAs grown under oxygen atmosphere and without any other intentional dopings. The principal shallow donor in this material is considered to be Si. All samples exhibited impurity-band conduction at low temperature. Electron concentrations in the conduction band were calculated, using a two-band model, and then fitted to the usual equation expressing charge neutrality. A value of 2.3 × 10−3 eV was obtained for the ionization energy of the donors, for donor concentration ranging from 5 × 1015 cm−3 to 2 × 1016 cm−3. The conduction in the impurity band was of the hopping type for these concentrations. A value of 3.5 × 1016 cm−3 was obtained for the critical transition concentration of the impurity-band conduction to the metallic type.

ENERGY BAND OVERLAPPING IN HIGH-Tc SUPERCONDUCTORS

1996 ◽  
Vol 10 (30) ◽  
pp. 1483-1490 ◽  
Author(s):  
M. MORENO ◽  
R. M. MÉNDEZ-MORENO ◽  
M. A. ORTIZ ◽  
S. OROZCO
Keyword(s):  
Weak Coupling ◽  
Cuprate Superconductors ◽  
Weak Coupling Limit ◽  
Band Model ◽  
Coupling Constant ◽  
High Tc Superconductors ◽  
Energy Bands ◽  
Effective Coupling ◽  
High Tc ◽  
Two Band Model

Multi-band superconductors are analyzed and the relevance of overlapping energy bands to the high-T c of these materials is studied. Within the BCS framework, a two band model with generalized Fermi surface topologies is developed. Values of the overlapped occupancy parameters for typical cuprate superconductors are obtained as a function of the ratio R and the effective coupling constant, λ, in the weak-coupling limit. The overlap scale is of the order or lower than the cutoff (Debye) energy. The typical behavior of the isotope effect is obtained. As these superconductors have transition temperatures above the phonon barrier, the results of this approach are important to the generic understanding of the high-T c superconducting mechanism.

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