Anomalies in the low-temperature thermal and electrical resistivities of copper

Abstract

Accurate measurements of the low-temperature thermal conductivity of high-purity copper have revealed abrupt changes in the temperature dependence of the inelastic electron-phonon scattering component of the thermal resistivity ( 8'~) at about 7-, 11, and 18 K. The existence of these regions and the deviation of the form of the ratio p"/Wz (where p" is the normal electron-phonon scattering coniponent of the electrical resistivity) in the two lower regions from that in the two upper regions requires a reassessment of the natures and forms of the electron scattering processes in Cu.

Reduction of the Lorenz Number in Copper at Room Temperature due to Strong Inelastic Electron Scattering Brought about by High-Density Dislocations

“…Here, for the convenience of discussion, we consider thermal resistivity (W = 1/κ). For a pure metal, it can be given as 30,31,42 W W W W…”

“…Fonteyn and Pitsi performed early experimental investigations on Cu in the low-temperature regime (0.5 < T < 3 K), but the torsion deformation was made only within a few percentages of strain. Later, Kos carried out experiments on low-temperature thermal and electrical transport of pure Cu and observed abrupt changes at 7, 11, and 18 K in the temperature dependence of the inelastic component of thermal resistivity ( W inelastic ), which is due to the vertical processes of inelastic electron–phonon scattering. The author also measured the low-temperature thermal conductivity of one deformed Cu sample that was strained by winding and compared it with the pristine sample to disclose the effect of dislocations .…”

“…Here, for the convenience of discussion, we consider thermal resistivity ( W = 1/κ). For a pure metal, it can be given as ,, where W 0 is due to residual electrical resistivity and W elastic and W inelastic are components due to elastic and inelastic electron scattering, respectively. W 0 = ρ 0 / L 0 T is typically about 10 –6 m K W –1 in this work (ρ 0 ≈ 10 –11 Ω m for Cu), which is about 3 orders of magnitude smaller than the total thermal resistivity.…”