Phonon-enhanced effective mass from thermopower oscillations in aluminum

The authors have measured the variation with magnetic field and temperature of the amplitude of giant quantum oscillations in the thermopower of aluminum from 1.7 to 4.8K in fields up to 21 kG. The field and temperature variations are dominated by a term exponential in the ratio m*(T+T D )/H. Analysis using the de Haas-van Alphen procedure for determining effective masses and Dingle temperatures yields m*=(0.093 +or-0.01)m e and T D approximately=1-4K. This value for m* agrees with the value obtained from de Haas-van Alphen measurements for the same electron orbit, and corresponds to a phonon-enhancement of approximately 40%.