On the theory of nonlinear dopplerons in metals

The possibility of the nonlinear wave propagation occurring in metals, such as cadmium, in the geometry where a constant magnetic field $\mathbf{H}$ is directed at an angle with respect to the hexagonal axis of the crystal has been investigated theoretically. In the linear regime in this geometry, there is a significant magnetic Landau damping, which prevents propagation of waves. It has been shown that the electron trapping by the magnetic field of a wave can substantially decrease the efficiency of this damping. As a result, the propagation of a doppleron, i.e., the mode related to the Doppler-shifted cyclotron resonance of electrons, becomes possible. It has been noted that a similar “bleaching” effect should also take place in some other metals.