Group velocity of bulk magnetoplasmons in electric-gyrotropic thin films: Faraday configuration

The behaviors of bulk magnetoplasmon waves in a magnetized electron gas thin film in the Faraday configuration, as an example of an electric-gyrotropic film, are investigated. General expression for dispersion relation of the waves is obtained by two different approaches. Also, energy distribution and power flow of bulk and surface magnetoplasmon waves are studied. Furthermore, the group velocity and associated group delay time of bulk magnetoplasmon modes are obtained exactly by several different theoretical methods, such as the well-known wave theory method, the zig-zag ray approach based on the stationary-phase method and also the zig-zag ray approach based on the energy concepts. It is shown that the results are in completely consistent with each other. •Dispersion relation of bulk magnetoplasmon waves is obtained by two different approaches.•There are an infinite number of bulk magnetoplasmon waves that have different wavenumbers.•Group velocity and associated group delay time of bulk magnetoplasmon waves are obtained by four different approaches.•Group delay time is produced partly at the boundaries of the film and partly inside the film.•Group delay time produced inside the film forms a major part of the overall group delay time of the bulk magnetoplasmon waves.