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Metal Fermi temperature

For electrons in a metal, these velocities are on the order of 10 cm s . The Fermi temperature Tp is defined by the relation... [Pg.228]

For the compound UPt3, the value for y amounts to 420 mJ/mol K2, whereas the values for A and X depend on the direction in which the resistivity and the susceptibility have been measured, although these results do not differ more than roughly a factor of two. To illustrate these findings, the specific heat of an artificial heavy-fermion compound is shown in fig. 1 in a plot of c/T versus T2 and compared with the result for, again, an artificial normal metal. For the effective Fermi velocity, vF, one deduces values of order 5x103 m/sec and for the effective Fermi temperature values between 10 and 100 K. [Pg.131]

Typical for heavy-fermion systems is the large value for re that can take values which are several orders of magnitude larger than what is found in normal metals. It implies that the effective mass has a large volume dependence as does the effective Fermi temperature. [Pg.132]

Now, typical Fermi temperatures in metals are of the order of 50 000 K. Thus, at room temperature, TIT is very small compared to one. So, one can ignore the Tdependence of p, to obtain... [Pg.432]

In the work of Lam et al.the Gibbs free energies for the hep, fee, and bcc structures were calculated. Several approximations were used to make the calculation tractable. First, the temperature dependence of Ggj. is neglected. The justification is that electronic excitations are negligible compared with phonon excitations at temperatures which are small compared to the Fermi temperature of the metal. Hence,... [Pg.365]

Hence, in general, the temperature of the metal for which it remains solid is much lower than the Fermi temperature. Therefore, we can consider that the metal always behaves as though the temperature was 0 K, and we can content ourselves with approximation [1.106]. The Fermi temperature defines the temperature beyond which the effects of Fermi-Dirac statistics begin to manifest themselves. We can write that ... [Pg.34]

At a temperature T, the eurve differs only very little from the cinve at 0 K, beeause of the exeellent approximation offered by relation [1.92] in respeet to the expansion [1.91] and by relation [1.106] in respect to the expansion [1.105], because the temperature of the solid metal is generally far lower than the Fermi temperature. [Pg.35]

Under conditions of very low temperatures and if e < g, the exponential in the denominator approaches e °°, leading to/(e) approaching 1. If e > g, however, the exponential approaches e and/(s) goes to zero. As temperature is reduced,/(e) displays an increasingly sharper cutoff at the point e = g it approaches the form of a step function /(e) = 1 for e < go and /e) = 0 for e > go/ where go is the chemical potential at T = 0. Eor valence electrons (conduction electrons) in metals, go may be on the order of several hundred kj moH, and then even at room temperatiue, the distribution of electrons is very close to a step function, go is called the Fermi energy, and gg/k is the Fermi temperature. [Pg.352]

MetaUic behavior is observed for those soHds that have partially filled bands (Fig. lb), that is, for materials that have their Fermi level within a band. Since the energy bands are delocalized throughout the crystal, electrons in partially filled bands are free to move in the presence of an electric field, and large conductivity results. Conduction in metals shows a decrease in conductivity at higher temperatures, since scattering mechanisms (lattice phonons, etc) are frozen out at lower temperatures, but become more important as the temperature is raised. [Pg.236]

It will be intriguing to theoretically examine the possibility of superconductivity in CNT prior to the actual experimental assessment. A preliminary estimation of superconducting transition temperature (T ) for metallic CNT has been performed considering the electron-phonon coupling within the framework of the BCS theory [31]. It is important to note that there can generally exist the competition between Peierls- and superconductivity (BCS-type) transitions in lowdimensional materials. However, as has been described in Sec. 2.3, the Peierls transition can probably be suppressed in the metallic tube (a, a) due to small Fermi integrals as a whole [20]. [Pg.48]

A semiconductor can be described as a material with a Fermi energy, which typically is located within the energy gap region at any temperature. If a semiconductor is brought into electrical contact with a metal, either an ohmic or a rectifying Schouky contact is formed at the interface. The nature of the contact is determined by the workfunction, (the energetic difference between the Fermi level and the vacuum level), of the semiconductor relative to the mclal (if interface effects are neglected - see below) 47J. [Pg.469]

In this equation v is a phonon frequency, such that hv is approximately k, with the Debye characteristic temperature of the metal. The quantity p is the product of the density of electrons in energy at the Fermi surface, N(0), and the electron-phonon interaction energy, V. [Pg.825]


See other pages where Metal Fermi temperature is mentioned: [Pg.3]    [Pg.33]    [Pg.67]    [Pg.368]    [Pg.31]    [Pg.13]    [Pg.323]    [Pg.528]    [Pg.43]    [Pg.124]    [Pg.125]    [Pg.388]    [Pg.49]    [Pg.1804]    [Pg.500]    [Pg.44]    [Pg.51]    [Pg.237]    [Pg.113]    [Pg.346]    [Pg.360]    [Pg.151]    [Pg.378]    [Pg.277]    [Pg.522]    [Pg.33]    [Pg.45]    [Pg.125]    [Pg.48]    [Pg.110]    [Pg.120]    [Pg.167]    [Pg.301]    [Pg.197]    [Pg.73]    [Pg.312]    [Pg.347]    [Pg.51]   
See also in sourсe #XX -- [ Pg.448 ]




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