The transport properties of the cubic alkaline earths Ca, Sr, and Ba

1978 ◽  
Vol 56 (1) ◽  
pp. 161-174 ◽  
Author(s):  
J. G. Cook ◽  
M. J. Laubitz
Keyword(s):  
Large Deviations ◽  
Transport Properties ◽  
Thermoelectric Power ◽  
Phonon Scattering ◽  
Thermal Resistivity ◽  
Elastic Electron ◽  
Phonon Drag ◽  
Alkaline Earths ◽  
Conductivity Function ◽  
Electron Phonon Scattering

The electrical resistivity (ρ), thermoelectric power(S), and thermal conductivity (κ) of two Sr samples and two Ba samples have been determined from 30 to 300 K. Large deviations from Matthiessen's rule (DMR) were observed. The estimated transport properties for ideally pure Sr and Ba indicate that these elements, like Ca, show large deviations from the Bloch–Gruneisen form for ρ(T) at all temperatures, large and positive diffusion thermopowers with a negative phonon-drag contribution, and large deviations from the Wiedemann–Franz relationship (DWFR). In these respects, they are much more like the transition metals than the monovalent metals.In the second, analytical, portion of the paper we study the DWFR in some detail. First, the effect of lattice conduction is estimated, and found to be large. Then, a function X(E) of the electron energy, closely related to the conventional conductivity function σ(E), is estimated from the ρ and S data now available for Ca, Sr, and Ba above 300 K, and used to compute S and the Lorenz function for elastic electron–phonon scattering below 300 K. Comparison with the experimental data indicates that the energy dependence of the electron parameters is responsible for the electronic DWFR, and effects the diffusion thermoelectric power. Such 'band effects' may also be seen in the thermal resistivity due to inelastic scattering in at least Sr. Regrettably, we are not able to explain the observed DMR.

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.

PHONON DRAG AND CARRIER DIFFUSION CONTRIBUTIONS IN THERMOELECTRIC POWER OF K3C60 FULLERIDES

2012 ◽  
Vol 01 (03) ◽  
pp. 1250027 ◽  
Author(s):  
DINESH VARSHNEY ◽  
RAJENDRA JAIN ◽  
NAMITA SINGH
Keyword(s):  
Relaxation Time ◽  
Thermoelectric Power ◽  
Phonon Scattering ◽  
Linear Temperature Dependence ◽  
Phonon Drag ◽  
Linear Temperature ◽  
Carrier Diffusion ◽  
Time Approximation ◽  
Relaxation Time Approximation ◽  
Heat Carriers

The thermoelectric power (S) of K3C60 fullerides is theoretically analyzed. Mott expression within parabolic band approximation is used to reveal the electron diffusive thermoelectric power (Sc diff ) following Fermi energy as electron parameter, Sc diff show linear temperature dependence. S infers a change in slope above transition temperature and become almost linear above 70 K. The phonon drag thermoelectric power (S ph drag ) is computed within relaxation time approximation when thermoelectric power is limited by scattering of phonons from defects, grain boundaries, phonons and electrons as carriers. The S ph drag of K3C60 is anomalous and it is an artifact of strong phonon-electron and phonon scattering mechanism. The thermoelectric power within relaxation time approximation has been taken into account ignoring a possible energy dependence of the scattering rates. Behaviour of S(T) is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between carrier diffusion and phonon drag contributions.

CARBON NANOTUBES AS A PERFECTLY CONDUCTING CYLINDER

2003 ◽  
Vol 13 (03) ◽  
pp. 849-871 ◽  
Author(s):  
TSUNEYA ANDO
Keyword(s):  
Carbon Nanotubes ◽  
Transport Properties ◽  
Phonon Scattering ◽  
Tight Binding ◽  
Point Of View ◽  
Potential Range ◽  
Theoretical Point ◽  
Binding Model ◽  
Long Wavelength ◽  
Electron Phonon Scattering

A brief review is given on electronic and transport properties of carbon nanotubes mainly from a theoretical point of view. The topics include a description of electronic states in a tight-binding model and in an effective-mass or k · p scheme. Transport properties are discussed including absence of backward scattering except for scatterers with a potential range smaller than the lattice constant, its extension to multi-bands cases, and long-wavelength phonons and electron-phonon scattering.

Transport properties of solid and liquid Cs

1982 ◽  
Vol 60 (12) ◽  
pp. 1759-1769 ◽  
Author(s):  
J. G. Cook
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Melting Point ◽  
Transport Properties ◽  
Thermoelectric Power ◽  
Electron Scattering ◽  
Thermal Resistivity

The thermal conductivity, electrical resistivity, and thermoelectric power of Cs have been measured from 40 K, through the melting point which is near 300 K, up to 600 K. The thermal resistivity of both solid and liquid Cs contains a contribution from electron–electron scattering, which agrees well with theory. The electrical resistivity shows an appreciable "premelting" effect, which is tentatively attributed to impurities.

Transport properties of the ferromagnetic metals. II. Nickel

1976 ◽  
Vol 54 (1) ◽  
pp. 92-102 ◽  
Author(s):  
M. J. Laubitz ◽  
T. Matsumura ◽  
P. J. Kelly
Keyword(s):  
Transport Properties ◽  
Electron Scattering ◽  
Phonon Scattering ◽  
Positive Slope ◽  
Ferromagnetic Metals ◽  
Subsequent Publication ◽  
Consistent Group ◽  
Characteristic Features ◽  
Normal Electron ◽  
Electron Phonon Scattering

We present new experimental results for the transport properties of Ni. In comparing these results to previously published values, we show that there exists a consistent group of experimental data which establishes reliably the transport properties of pure Ni from perhaps 30 to 1500 K. In the paramagnetic range (T > 630 K), these properties show three characteristic features: a positive slope of the thermal conductivity (which is equivalent to an electrical resistivity increasing less than linearly with temperature), a large negative thermopower, and a Lorenz function substantially larger than the Sommerfeld value, L0. In attempting to provide an explanation of these features, we have discovered that the model of Mott, wherein the electronic relaxation time is inversely proportional to the density of states, does not appear to be universally valid and, more importantly, that the observed properties cannot be consistently explained if we assume pure electron–phonon scattering. To achieve consistency, at least one other scattering mechanism has to be included, such as normal electron–electron scattering; this will be taken up in detail in a subsequent publication.

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.

Anisotropic Normal State Transport Properties of Oxide Superconductors Predicted from Lapw Band Structures

1987 ◽  
Vol 99 ◽  
Author(s):  
Philip B. Allen ◽  
Warren E. Pickett ◽  
Henry Krakauer
Keyword(s):  
Single Crystal ◽  
Transport Properties ◽  
Normal State ◽  
Phonon Scattering ◽  
Oxide Superconductors ◽  
Band Structures ◽  
Electron Phonon Scattering

ABSTRACTThe resistivity, Hall, and thermopower tensors are calculated for the normal state of oxide superconductors on the assumption of band quasiparticle behavior. The shape of the resistivity ραβin the metallic a-b plane is consistent with ordinary impurity and electron-phonon scattering, but the magnitude is larger than predicted. The Hall tensor is predicted to be hole-like for orbits in the a-b plane but electron-like for a-c or b-c orbits, while the thermopower is predicted to be electron-like in the a-b plane and hole-like along the c-axis. Single crystal experiments have confirmed some of these predictions for the Hall tensor.

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