Low Temperature Physics: 37, 806 (2011); https://doi.org/10.1063/1.3670021 (6 pages)
Fizika Nizkikh Temperatur: Volume 37, Number 9-10 (September 2011), p. 1011-1018 ( to contents , go back )
Oscillations of kinks on dislocation lines in crystals and low-temperature transport anomalies as "passport" of freshly induced defects
L.P. Mezhov-Deglin1 and S.I. Mukhin1,2
1Institute of Solid State Physics RAS, Chernogolovka, Moscow district 142432, Russian Federation
2National University of Science and Technology "MISIS"
Received March 28, 2011
A possible interpretation of experimental data on low-temperature transport anomalies in weakly deformed ultra-pure metal crystals of lead, copper and aluminum and in 4He crystals is discussed in light of the proposed earlier theoretical picture of dislocations with dynamic kinks. The theoretical predictions give an overall picture of interaction of conduction electrons in ultrapure crystals with freshly introduced dislocations containing dynamic kinks in the Peierls potential relief. At random stresses caused by plastic deformation of the specimen, the kinks in the dislocation line form a set of one-dimensional oscillators in the potential wells of different shapes. At low temperatures, for sufficiently low density of defects that pin the kinks, the inelastic electron scattering by the kinks should lead to deviations from the Wiemann–Franz law. In particular, the inelastic scattering on the kinks should rezult in a quadratic temperature dependence of electronic thermal conductivity of a metallic sample along the predominant directions of the axes of dislocations. In the normal to dislocation axis plane dominanat is an elastic scattering of electrons at large angles. Pinning of kinks by point defects or additional dislocations, as well as annealing of the crystal that leads to the disappearance of the kinks, should lead to the suppression of the transport anomalies. Thus, the energy interval accommodating the vibrational spectrum of kinks is a “passport of deformation history” of each particular sample. It lies in the range bound by the characteristic value of the Peierls relief. For example, for copper it corresponds to temperatures / energies of 1 K. Next time we plan to discuss the applicability of the mechanism of phonon scattering by mobile dislocation kinks and pinning of kinks by impurities and thus to explane the anomalies in phonon thermal conductivity of 4He crystals and deformed crystals of pure lead in superconducting state.
PACS: 72.10.–d Theory of electronic transport; scattering mechanisms;
Key words: low temperatures, kinks on the dislocation lines, Peierls potential relief, Wiedemann-Franz law.