Broadband transverse electric surface wave in silicene

Abstract

Transverse electric (TE) surface wave in silicine is theoretically investigated. The TE surface wave in silicene is found to exhibit better characteristics compared with that in graphene, in terms of a broader frequency range and more confinement to the surface which originate from the buckled structure of silicene. We found that even undoped silicene can support the TE surface wave. We expect to obtain the similar characteristics of the TE surface wave in other two-dimensional materials that have slightly buckled honeycomb lattice.PACS numbers: 72.20. Pa,73.50.Lw Surface electromagnetic waves, or simply surface waves are electromagnetic (EM) waves that propagate on the surface of a material 1 . Surface waves recently have attracted a lot of interest, because of their capability to transport the EM energy on the surface 1-6 . There are two kinds of surface waves based on their polarizations; the transverse magnetic (TM) and transverse electric (TE) surface waves. In the case of TM surface wave, the component of magnetic field is transverse to the propagation direction, while the electric field has a component parallel to the propagation direction. The TM surface wave that also refers to a surface plasmon, can be seen as an electric dipole wave on the surface of material due to spatial perturbation of charge density 7,8 . On the other hand, the TE surface wave has the component of electric field transverse to the propagation direction while the magnetic field has a component parallel to the direction of propagation. The TE surface wave can be seen as a magnetic dipole wave on the surface of material due to the self-sustained surface current oscillation 7,8 .It is important to note that the radiation loss of magnetic dipole is much smaller than that of electric dipole 9 . Therefore, the TE surface wave can propagate longer than TM surface wave 10,11 , which makes the TE surface wave desirable for the transporting EM energy over long distance 7,11 . However, the TE surface wave cannot exist on the surface of an conventional bulk metal because condition for generating the TE mode is limited which means that the induced surface current is not available in the conventional bulk metal 1,2,7,12 . Some efforts have been made for designing artificial materials so that the TE surface wave can be generated, such as metamaterials and a cluster of nanoparticles, which are generally complicated, hence making them less viable and accessible 3,7,11,13 .The difficulties of generating the TE surface wave can be alleviated by using two-dimensional (2D) materials such like graphene, which is a monolayer of carbon atoms arranged in honeycomb lattice 14,15 . Mikhailov and Ziegler have shown that, when the imaginary part of optical conductivity of 2D material is negative (posi- tive), the TE (TM) surface wave can propagate on the surface of the 2D materials 15 . Due to the presence of the Dirac cone in its electronic structure, the imaginary part of optical conductivity of graphene can be negative at a certain frequency range. This ...

Confined transverse electric phonon polaritons in hexagonal boron nitrides

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First designing of a silicene-based optical MOSFET with outstanding performance

“…Ukhtary et al showed that by applying , TE waves can be propagated in a larger frequency range for silicene. While the TE wave propagation range for graphene is only possible in a narrow frequency range of 49 , it can be increased for silicene by increasing . Hence, an OMOSFET was designed in the present study using this feature of silicene.…”

“…According to for TE waves 49 , where is the optical confinement length and is the vacuum permeability, better propagation of surface waves occurs at smaller values of . As a result, larger values of the imaginary part of conductivity ( ) provide smaller values of the confinement length.…”

Confined transverse-electric graphene plasmons in negative refractive-index systems

“…This way, highly confined graphene plasmons can be achieved without stringent requirement on the polarization of light and can benefit more practical applications based on TE waves. Such a quest still remains elusive, although many researches of TE polaritons in graphene [26][27][28][29] and other 2D materials [30][31][32][33][34] have been ignited by the pioneering work in 2007.…”