Observation of giant dielectric constant in an assembly of ultrafine Ag particles

Although the Gor'kov-Eliashberg effect in isolated ultrafine metal particles is forbidden due to the depolarization field inside it, a giant dielectric response (ε~10¹⁰) is observed in an assembly of ultrafine metal particles connected to each other forming an interrupted metal strand. The metal strand, which has a very low depolarization field, is obtained by the application of electric field to the assembly of isolated minute metal particles. The strong electrostatic force due to high electric field (10⁶V/cm) in the nano air gap between the particles causes the particles to deform in the direction of the electric field and finally attains the percolating configuration with the formation of a metal filament, the electronic wave functions of which are localized due to lattice defects at the interface between the particles.