Step-like conductance of a silicene pseudospin junction

A step-like conductance as a function of the Fermi energy is theoretically predicted for a junction made of silicene, in which the energy gap in the junction can be controlled by a perpendicular electric field. When the electric field is applied at the central area of the junction, the transmission probability of an electron becomes partially suppressed and the calculated conductance behaves a step-like function of the Fermi energy. Origins of the step-like conductance are (1) formation of a standing-wave of electron, (2) changing number of transport channels and (3) a rotation of out-of-plane pseudospin of the electron in silicene. We analytically show that the transmission probability of the electron through the junction depends on the direction of the pseudospin, in which the large rotation results in a vanishing conductance. When we switch-off the electric field, on the other hand, the pseudospin does not change the direction, which gives a finite conductance. Thus a switching device can be realized in the silicene pseudospin junction.