Evidence for collective linear conduction in the Peierls conductor o-TaS_3

TL;DR

This study reveals that in the Peierls conductor o-TaS_3, low-temperature conduction is dominated by collective excitations rather than single-particle electrons and holes, with activation energy about half the Peierls gap.

Contribution

It provides experimental evidence that collective excitations, not single particles, dominate low-temperature conduction in o-TaS_3, challenging previous assumptions.

Findings

Low-temperature conduction is mainly due to collective excitations.

Activation energy of collective excitations is about half the Peierls gap.

Single-particle excitations play a minor role in conduction at low temperatures.

Abstract

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.