Thermoelectric power of metallic Rb_3 C_60: phonon-drag and carrier diffusion contributions

Thermoelectric power (5) of rb_3 c_60 fullerides in the metallic phase is theoretically estimated. we first develop a hamiltonian model that incorporates the scattering rates within the relaxation time approximation to estimate the phonon-drag thermoelectric power (s^drag_ph) incorporating the scattering of phonons with defects, electrons as carriers, grain boundaries, and phonon-phonon interactions. as a next step, mott expression within parabolic band approximation is used to analyze the electron diffusive thermoelectric power (s^diff_c) using fermi energy as electron parameter, and s^diff_c shows a linear temperature dependence. the s^drag_ph is nonzero in both normal and superconducting states. its behavior is determined by competition among the several operating scattering rates for heat carriers and a balance between diffusive carrier and phonon-drag contributions. acoustic phonons are effectively scattered by various scatterers for the thermoelectric power. s infers a change in slope above transition temperature and becomes almost linear above 70 k.