Phonon-drag effect in TiSe2-xSx mixed compounds.

Abstract

Thermoelectric power (TEP) measurements of ${\mathrm{TiSe}}_{2\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{S}}_{\mathrm{x}}$ solid solutions have been performed in the temperature range 10--315 K for 0\ensuremath{\lesssim}x<2. A phonon-drag effect is identified around 25 K. Its contribution to the TEP has been analyzed as a function of x. An estimate of the electron-phonon relaxation time ${\ensuremath{\tau}}_{e\mathrm{\ensuremath{-}}\mathrm{ph}}$ is derived from this analysis. This estimate is found to be in accordance with the value of ${\ensuremath{\tau}}_{e\mathrm{\ensuremath{-}}\mathrm{ph}}$ obtained from theoretical predictions.