Scaling and universality of ac conductivity and dielectric response in disordered materials under pressure

Scaling of physical quantities describing the ac response is a common feature of disordered matter, while in some cases, empirical functions have been proposed. The exact forms of analytic functions that scale complex conductivity and permittivity are derived in this work by exploring the effect of pressure at various temperatures on the ac conductivity of polypyrrole. The scaling behavior is visualized within the frame of percolation and self-similarity.