ZERO-BIAS ANOMALY OF POINT-CONTACT RESISTANCE DUE TO ADIABATIC ELECTRON RENORMALIZATION OF DYNAMICAL DEFECTS

We study the effect of the adiabatic electron renormalization on the p arameters of the dynamical defects in the ballistic metallic point con tact. The upper energy states of the ''dressed'' defect are shown to m ake a smaller contribution to a resistance of the contact than the low er-energy ones. This holds both for the ''classical'' renormalization related to defect coupling with average local-electron density and for the ''mesoscopic'' renormalization caused by the mesoscopic fluctuati ons of electronic density the dynamical defects are coupled with. In t he case of mesoscopic renormalization, one may treat the dynamical def ect as coupled with Friedel oscillations originated by the other defec ts, both static and mobile. Such coupling lifts the energy degeneracy of the states of the dynamical defects making a different mesoscopic c ontribution to resistance, and provides a model for the fluctuator tha t pictures it as the object originated by the electronic mesoscopic di sorder rather than by the structural one, The correlation between the defect energy and the defect contribution to the resistance leads to z ero-temperature and zero-bias anomalies of the point-contact resistanc e. A comparison of these anomalies with those predicted by the two-cha nnel Kondo model (TCKM) is made. It is shown, that although the propos ed model is based on a completely different from TCKM physical backgro und, it leads to a zero-bias anomalies of the point-contact resistance , which are qualitatively similar to TCKM predictions.