Electrical and optical conductivities of bilayer silicene: Tight-binding calculations

Abstract

The electronic structures, densities of state and electrical and optical conductivities of monolayer and bilayer silicene sheets are investigated using tight-binding approximation and Green’s function method. We found that applying the electric field on doped bilayer silicene leads to band structure modification. For AA-stacked bilayer silicene, applying and increasing the bias [Formula: see text] does not create the energy gap but for AB-stacked bilayer, a small bias [Formula: see text] is enough to create an energy gap. It is shown that the electrical conductivity depends on temperature, doping and electric field. In pristine and doped AA- and AB-stacked bilayers, electrical conductivity increases (decreases) linearly with [Formula: see text] at low (high) temperature and decreases by increasing the doping onsite energy [Formula: see text] at all [Formula: see text] ranges. The effects of temperature on the conductivity increase with the increase of electric field. It is found that the electrical conductivity depends on the amount of interlayer hopping integral [Formula: see text]. For the case of AA-stacking, there are three steps in optical conductivity at energies [Formula: see text] and [Formula: see text] for [Formula: see text] and [Formula: see text]. For the case of AB-stacking the optical conductivity has a step at [Formula: see text] similar to monolayer sheet and some steps at energies [Formula: see text].