Azbel'-Kaner Cyclotron Resonance and Magnetic Surface Levels in Beryllium

Azbel'-Kaner cyclotron resonance in beryllium has been used to investigate the angular dependence of effective masses in the ($10\overline{1}0$) and (0001) planes. The samples studied had a residual resistivity ratio of ∼ 2000, producing at helium temperatures and 35-GHz values of $\omega \tau$ of approximately 10. Resonances were observed from belly and neck holes on the second-zone coronet and from electrons on the third-zone cigars. Where possible, results have been compared with effective masses obtained in de Haas-van Alphen experiments. Surface-impedance oscillations due to magnetic surface levels were also observed at low magnetic fields and 35 GHz. Oscillations due to electrons of two different sections of the Fermi surface can be distinguished in angular studies in the ($10\overline{1}0$) plane. One set of oscillations, centered about the $〈11\overline{2}0〉$, has been ascribed to holes on the coronet necks. A second set, observed about the $〈0001〉$, is due either to holes on the ridge of the coronet belly or electrons on the ridge of the cigar waist. A comparison of the Fermi-surface parameters obtained in the surface-level experiments is made with known values for beryllium.