| 1. |
- Neve, Jesper, et al.
(author)
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Electron band structure, resistivity, and the electron-phonon interaction for niobium under pressure
- 1983
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In: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 28:2, s. 629-637
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Journal article (peer-reviewed)abstract
- Accurate measurements of the electrical resistance of Nb are presented as a function of temperature and pressure in the region 0-40°C and 0-1 GPa. From these measurements and published results for the compressibility and the pressure dependence of the superconducting transition temperature Tc we evaluate the pressure dependence of the electron-gas plasma frequency ω(p). The electronic structure of Nb is calculated from a self-consistent linear muffin-tin orbital method and results are obtained for the pressure dependence of the density of states at the Fermi surface, the root mean square over the Fermi surface of the Fermi velocity, the optical mass, and the plasma frequency. The experimental and calculated results for the pressure dependence of ω(p) are both close to dlnω2 / dlnV=-1.9. This agreement suggests that measurements of the electrical resistance as a function of temperature and pressure provide a new test of band-structure calculations. From our measurements of the resistance and calculations of ω(p) and from published results for the compressibility we obtain the pressure dependence of the electron-phonon interaction λ(p). With p given in gigapascals, the result is dlnλ / dp=-0.0047.
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| 2. |
- Rapp, Östen, et al.
(author)
-
Possibility of superconductivity in palladium at high pressures
- 1984
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In: LT-17. - Amsterdam : North-Holland: Elsevier Science Publishers B.V.. - 0444869107 ; , s. 865-866
-
Conference paper (peer-reviewed)abstract
- On the basis of measurements of the resistivity and calculations of the density of states and the plasma frequency it is concluded that palladium may become superconducting at high pressures.
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| 3. |
- Rapp, Östen, et al.
(author)
-
The pressure dependence of of the electron-phonon interaction and the normal state resistivity
- 1981
-
In: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 24:1, s. 144-154
-
Journal article (peer-reviewed)abstract
- Accurate measurements of the electrical resistance as a function of temperature and pressure are reported for Sn, Zr, dhcp La, and V. These measurements cover a temperature region around room temperature and pressures up to 1.3 GPa. From these data, including also our previous measurements for Al and published results for Pb, the pressure dependence of d ρ / dT (the resistivity-temperature derivative) is obtained. This quantity is found to be a significant factor in the pressure dependence of the electron-phonon interaction parameter λ. For the nontransition metals the relative pressure dependence of d ρ / dT is much larger than the compressibility. Therefore the pressure dependence of the superconducting Tc is quantitatively well accounted for by the resistance data for these metals. For the transition metals the pressure dependence of d ρ / dT is relatively smaller and Tc(p) calculated from the resistance data is, at the best, only qualitatively correct. These differences are discussed. Estimates for the pressure dependence of the plasma frequency are obtained.
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