Evidence for collective linear conduction in the Peierls conductor   o-TaS_3
  Using photoconduction study we demonstrate that the low-temperature Ohmic conduction of TaS$_3$ is not provided by single-particle excitations -- electrons and holes excited over the Peierls gap. Instead, the low-temperature Ohmic conduction is mostly provided by collective excitations having the activation energy about half of the Peierls gap value and shunting the contribution of electrons and holes. 
S.V. Zaitsev-Zotov and V.E. Minakova