Breakdown of Pippard ineffectiveness condition for phononelectron scattering in micro and nanostructures

The Pippard ineffectiveness condition -that electrons strongly scattering f rom impurities and defects are ineffective in scattering phonons- is based on the assumption that electron scatterers vibrate in the same way as the h ost lattice. Then the relaxation rate of a low-energy phonon with the wave vector q is 1/tau(ph-e) similar to u(2)q(2)l/v(F) (u and v(F) are the sound velocity and Fermi velocity, l is the electron mean free path). Boundaries and defects moving differently from host lattice drastically change the ch aracter of the interference between scattering processes and increase the p honon-electron coupling. In the presence of the quasistatic potential the p honon relaxation is (q(2)lL)(-1) times faster: 1/tau(ph-e) similar to u(2)/ (v(F)L) (L is the electron mean free path with respect to scattering from t he quasistatic potential). Analogous effect is expected for phonons with om ega similar to 0.01 omega(D) (omega(D) is the Debye frequency) in conductor s with substitutional disorder.