A new type of charge-density-wave pinning in orthorhombic TaS$_3$ crystals with quenching defects

Diminishing in the concentration of quenching defects during thermocycling of orthorhombic TaS$_3$ samples in the temperature range below the Peierls transition temperature $T<T_{\mathrm{P}}$ is observed. It makes it possible to study the character of pinning of the charge density wave by these defects. A number of fundamental differences from pinning by ordinary local pinning centers—impurities and point defects—have been found. We conclude that quenching defects are extended (non-local) objects (presumably, dislocations) that can diffuse from the crystal during low-temperature thermocycling due to their strong interaction with the charge density wave, which is intrinsic for Peierls conductors. The presence of these defects leads to a previously unknown non-local type of the charge-density-wave pinning that acts on $T_{\mathrm{P}}$ and the threshold field for the onset of charge-density-wave sliding, $E_{\mathrm{T}}$, differently in comparison with the local pinning centers.