Anomalous Frequency-Dependent Conductivity of Polyacetylene

Abstract

The frequency ($f$) and temperature ($T$) dependent conductivity ($\ensuremath{\sigma}$) is reported for cis-${(\mathrm{CH})}_{x}$, trans-${(\mathrm{CH})}_{x}$, and ammonia-compensated ${(\mathrm{CH})}_{x}$. A strongly $T$-dependent dc $\ensuremath{\sigma}$ together with a weakly $T$-dependent ac $\ensuremath{\sigma}$ were observed for predominantly cis-${(\mathrm{CH})}_{x}$ and for N${\mathrm{H}}_{3}$-compensated samples, similar to $\ensuremath{\sigma}(f,t)$ of many semiconductors. The trans-${(\mathrm{CH})}_{x}$ has a larger "weakly" $T$-dependent dc $\ensuremath{\sigma}$ and anomalous strongly $T$-dependent ac $\ensuremath{\sigma}$. The latter results are in good agreement with Kivelson's theory of charge transport via intersoliton electron hopping.