Casimir force between two parallel semiconductor slabs: Magnetic field effects in the Voigt geometry

We investigate the Casimir force F between two parallel semiconductor slabs taking into account magnetoplasmon effects. For our calculations we consider an external magnetic field applied in the Voigt geometry. Studies are carried out using the formula of F, which is written in terms of the reflectivities of the incident electromagnetic (EM) waves onto the surfaces of the semiconductor slabs, in the vacuum gap between slabs. Results show that the Casimir force depends strongly on the slab thickness as well as on the magnetic-field strength (or equivalently on the cyclotron frequency). At a constant cyclotron frequency and for small slab thickness F/F-0 (F-0 is the ideal force) displays a dip at small separation distances L between slabs. F/F-0 increases with L up to saturation as the slab thickness increases. The curve with the strongest value of F/F-0 corresponds to the semi-infinite medium geometry. For a constant slab thickness and small cyclotron frequency, F/F-0 as a function of L shows a monotonic increase as L increases, and eventually reaches saturation. At high cyclotron frequency F/F-0 displays a dip. The curve of F/F-0 with no applied external field corresponds to the one with the strongest Casimir force. Therefore, magnetoplasmon effects, with an applied magnetic field in the Voigt geometry may inhibit the Casimir force. (c) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim