Doppler-shifted acoustic cyclotron resonance in aluminum

Abstract

Doppler-shifted cyclotron resonances (DSCR) have been observed with longitudinal and transverse acoustic waves propagating along the [001], [111], and [110] axes of pure aluminum crystals. One to three distinct series of resonance peaks have been observed in each field direction. The harmonic numbers of most DSCR series follow the selection rules for propagation along high symmetry axes. Except in the case ofB parallel to [110], the peak fields of the harmonics are inversely proportional to the harmonic numbers. Most of the DSCR series are identifiable with known DSCR zones on the Fermi surface, the area derivatives of which are then deduced. The area derivative data obtained are either more accurate or are complementary to those measured by helicon DSCR and magnetomorphic size-effect experiments. Values for Fermi surface area derivatives are compared with those calculated from two current models for the aluminum Fermi surface. Both the caps in [001] and [111] directions are shown to be free-electron-like.