  We study the electrical modulation of the transport properties of silicene
constrictions with different geometrical structures by adopting the
tight-binding model and non-equilibrium Green's function method. The band
structure and transmission properties are discussed under the influence of the
external electric field and potential energy. Especially, we investigate the
effects of the position and width of the central scattering region on the
conductance with increasing of Fermi energy. We find that the conductance
significantly depends on the position and the width. Interestingly, the
symmetrical structure of the central region can induce a resonance effect and
significantly enlarge the system's conductance. Obviously, we obtain an
effective method to adjust the transport property of the silicene
heterojunctions. Correspondingly, we propose a novel two-channel structure with
an excellent performance on the conductance compared to the one-channel
structure with the same total width.
