INTERACTION OF NONEQUILIBRIUM PHONONS WIT H AN INTERNAL BOUNDARY (TWIN BOUNDARY) IN BISMUTH

A study is made of the mechanism of interaction of non-equilibrium pho nons generated in bismuth single crystals in the non-linear conductivi ty regime (Esaki effect) with boundaries of twin layers. Current-volta ge characteristics and signals of a non-linear response are investigat ed at liquid helium temperatures as well that of the pumping-out of li quid hydrogen vapour. It has been found that under the orientation of the magnetic field vector close to the direction parallel to the plane of twinning the non-stationary process arises and its duration tau(x) exceeds by an order of magnitude the characteristic stabilization tim es of non-equilibrium phonons. Dependences of tau(x) On magnitude and direction of the magnetic field, temperature and electric current are measured. The twin layer is considered asa simple's inner boundary whe re the diffusive static skin-effect is realized. The experimental resu lts may be interpreted under the certain assumptions which are rather difficult to substantiate convincingly. (In particular by the assumpti on about anomalously high probability of absorption of non-equilibrium phonons in the skin-layer). Nevertheless the proposed model of the ph enomenon observed allows ones to desctibe both the non-stationary proc ess (i.e. all singularities of a complicated response signal) and it's dependences oil external parameters (current, magnetic field and temp erature).