INTERRELATION OF RESISTIVITY AND INELASTIC ELECTRON-PHONON SCATTERINGRATE IN IMPURE NBC FILMS

A complex study of the electron-phonon interaction in thin NbC films w ith electron mean free path l=2-13 nm gives strong evidence that elect ron scattering is significantly modified due to the interference betwe en electron-phonon and elastic electron scattering from impurities. Th e interference T-2 term, which is proportional to the residual resisti vity, dominates over the Bloch-Gruneisen contribution to resistivity a t low temperatures up to 60 K. The electron energy relaxation rate is directly measured via the relaxation of hot electrons heated by modula ted electromagnetic radiation. In the temperature range 1.5-10 K the r elaxation rate shows a weak dependence on the electron mean free path and strong temperature dependence similar to T-n, with the exponent n = 2.5-3. This behavior is explained well by the theory of the electron -phonon-impurity interference taking into account the electron couplin g with transverse phonons determined from the resistivity data.