Thermoelectric power of TaS3

Thermoelectric power measurements have been made on well characterized crystals of orthorhombic TaS₃ as a function of temperature down to 80 K. A negative thermopower as for electrons is observed over the entire range, and the Peierl's transition is readily observable at 215 K. A sudden increase occurs around 160 K thereafter the magnitude of thermopower rises upon further cooling to values as high as 800 μV/K. This giant thermopower suggests that below about 160 K solitons or charge density wave dislocations dominate the low field electrical conduction instead of thermally excited electrons.