Modeling the thermopower of icosahedral Al_(63)Cu_(25)Fe_(12) quasicrystals: spectral fine structure

Abstract

On the basis of a realistic model for the spectral conductivity, obtained from a proper combination of tunneling spectroscopy [R. Escudero , J. Phys.: Condens. Matter 11, 383 (1999)] and transport measurements, we derive a closed analytical expression for the Seebeck coefficient, satisfactorily describing its temperature dependence over a wide temperature range. The relative importance of thermal broadening effects and the temperature dependence of chemical potential in the thermopower curve is quantitatively discussed. By comparing the obtained analytical results with the experimental S(T) curve evidence for band structure effects in the thermopower is reported.