INELASTIC RELAXATION-TIME OF ELECTRONS IN DISORDERED BISMUTH-FILMS - DIRTY LIMIT

The behavior of the quantum corrections to the magnetoconductivity of thin bismuth films (approximately 100 angstrom thick) which are associ ated with weak localization of electrons has been investigated in the temperature range 0.3-10 K, with electron overheating. Temperature dep endences of the time tau(eph) of electron-phonon energy relaxation and the time tau(eph)i corresponding to the electron-phonon contribution to phase electron relaxation have been obtained from the experimental data. The theoretically predicted weakening of electron-phonon interac tion in the case of the inequality q(ph) l < 1 providing the so-called <<dirty>> limit (q(ph) is the thermal phonon wave vector and l is the electron mean free path) has been experimentally observed for the fir st time. The <<dirty>> limit was attained by two method: artificial de crease of the mean free path l and lowering of the temperature to belo w the characteristic temperature T2 = HBARs(l,t)/kl (s(l,t) being the phonon velocity), which is about 1 K for l almost-equal-to 100 angstro m. As temperature lowers, the relation tau(eph)-1 is-proportional-to T 3 gives way to tau(eph)-1 is-proportional-to T4 at 1,2 K, in good agre ement with estimates for T2 in the films under study.