Cyclotron resonance in lead —I: Tipping effect of magnetic field

The cyclotron resonances in lead in field tipped geometry have been observed for large tipping angles up to 40° from the sample surfaces of the (111) and (100) planes. In addition to the resonance of the orbit ζ on a cylindrical arm of the electron Fermi surface, two new series of resonances, ζ^A and ζ^B have been found, of which the clotron masses are very close to that of ζ but which differ slightly in tipping angle dependence. The mass of ζ^A is dependent on microwave frequency, so that ζ^A is attributed to the Doppler-shifted cyclotron resonance of a non-stationary orbit near, ζ, whose location is discussed in relation to the Fermi surface model of Van Dyke. In field geometry normal to the (100) surface, two series of resonances have been observed, which are characterized as the extinction of even numbered harmonic resonances. This effect arises from the skipping orbit which has a trajectory topologically similar to a baseball seam in real space. One of these series is attributed to the orbit v around the junction of four electron arms.