Phenomenological model of giant piezodielectric effect in GaSe layered crystals

Abstract

Piezodielectric effect has been considered in frequency-dispersive systems dielectric response of which at low-frequencies obeys power fractional law B(j ) −(1−n) , where j is the imaginary unit, is the cyclic frequency, and n ≈ 0.8 . This type of dispersion is characteristic for solids with hopping electrical charge carriers. A phenomenological model describing the influence of uniaxial mechanical strain on the low-frequency dielectric spectra and their parameters has been proposed. The model explains that as there is increase of real and imaginary parts of complex relative dielectric constant, there is decrease of exponent n with increasing uniaxial strain. Sensitivity of parameters B and n of dielectric spectra with n ≈ 0.8 (characteristic for hopping charge carrier systems) and parameters of effective dipoles on uniaxial pressure has been estimated for high-resistivity GaSe layered crystals.