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

Abstract

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/F0 (F0 is the ideal force) displays a dip at small separation distances L between slabs. F/F0 increases with L up to saturation as the slab thickness increases. The curve with the strongest value of F/F0 corresponds to the semi‐infinite medium geometry. For a constant slab thickness and small cyclotron frequency, F/F0 as a function of L shows a monotonic increase as L increases, and eventually reaches saturation. At high cyclotron frequency F/F0 displays a dip. The curve of F/F0 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. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Van der Waals torque induced by external magnetic fields

“…In the Voigt geometry the external magnetic field points along the z axis. In this case, the components of the dielectric tensor are given by [29,48]…”

“…The study of the of Casimir and Van der Waals forces in MEMS, in particular its role in pull-in dynamics has been also a topic of intensive study [23][24][25][26][27][28]. A possibility that has been considered by the authors [29][30][31] is the use of external magnetic fields to decrease the magnitude of the Casimir force, and thus inhibiting the pull-in or jump to contact.…”

Pull-in control due to Casimir forces using external magnetic fields

“…In this paper we present a theoretical calculation of the effect of an external magnetic field on the stability of a capacitive micro/nano switch, when the only force of attraction present is the Casimir force. This external magnetic field can be used to control the pullin dynamics since the Casimir force decreases with increasing magnetic field due to the excitation of magnetoplasmons [21].…”

“…The reflectivities for s and p polarized waves in the Voigt configuration can be calculated using the surface impedance approach, as recently shown by [21]. Using Eq.…”

“…( 1) the Casimir force between the plates for different values of ω c was calculated by , showing a reduction of the Casimir force as a function of magnetic field. [21].…”