Phonon-drag effect inTiSe2−xSxmixed compounds

Thermoelectric power (TEP) measurements of ${\mathrm{TiSe}}_{2\mathrm{-}\mathrm{x}}$ ${\mathrm{S}}_{\mathrm{x}}$ solid solutions have been performed in the temperature range 10–315 K for 0≲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 ${\tau }_{e\mathrm{-}\mathrm{ph}}$ is derived from this analysis. This estimate is found to be in accordance with the value of ${\tau }_{e\mathrm{-}\mathrm{ph}}$ obtained from theoretical predictions.