Band Structure Of Silicene Research Articles

Optical and electric control of charge and spin-valley transport in ferromagnetic silicene junction

We theoretically investigate the charge and spin-valley transport in a normal/ferromagnetic/normal silicene junction, where the ferromagnetic region is exposed to an off-resonant circularly polarized light and perpendicular electric field. We show that one wider transport gap can be produced by the optical field than the electric field, which provides a simple way to fabricate an optical controlled on/off switch. On the other hand, in the presence of a proper optical field and ferromagnetic exchange field, the spin-polarized conductance is enhanced above 90%, and the polarized direction can be inverted just by reversing the polarization of the light. Additionally, the valley-polarized conductance is sensitive to the optical and electric field, under proper values, one near perfect K(K′) valley-polarized conductance exceeding 95% is realized. All these findings are well understood from the band structure of silicene and expected to be beneficial for real applications in high performance spintronics and valleytronics.

Band structure of silicene in the tight binding approximation

The electronic structure of silicene is simulated by the tight binding method with the basis sp3d5s*. The results are in good agreement with ab initio calculations. The effective Hamiltonian of silicene in the vicinity of the Dirac point is constructed by the method of invariants. Silicon atoms in silicene are located in two parallel planes displaced perpendicularly to each other by Δz; the energy spectrum essentially depends on this displacement. Using the tight binding technique, the coefficients of the effective Hamiltonian are determined for various values of Δz.

Spin helical states and spin transport of the line defect in silicene lattice

We investigated the electronic structure of a silicene-like lattice with a line defect under the consideration of spin–orbit coupling. In the bulk energy gap, there are defect related bands corresponding to spin helical states localized beside the defect line: spin-up electrons flow forward on one side near the line defect and move backward on the other side, and vice versa for spin-down electrons. When the system is subjected to random distribution of spin-flipping scatterers, electrons suffer much less spin-flipped scattering when they transport along the line defect than in the bulk. An electric gate above the line defect can tune the spin-flipped transmission, which makes the line defect as a spin-controllable waveguide. • Band structure of silicene with a line defect. • Spin helical states around the line defect and their probability distribution features. • Spin transport along the line defect and that in the bulk silicene.

Band structure of silicene on zirconium diboride (0001) thin-film surface: Convergence of experiment and calculations in the one-Si-atom Brillouin zone

So far, it represents a challenging task to reproduce angle-resolved photoelectron (ARPES) spectra of epitaxial silicene by first-principles calculations. Here, we report on the resolution of the previously controversial issue related to the structural configuration of silicene on the ZrB$_2$(0001) surface and its band structure. In particular, by representing the band structure in a large Brillouin zone associated with a single Si atom, it is found that the imaginary part of the one-particle Green's function follows the spectral weight observed in ARPES spectra. By additionally varying the in-plane lattice constant, the results of density functional theory calculations and ARPES data obtained in a wide energy range converge into the "planar-like" phase and provide the orbital character of electronic states in the vicinity of the Fermi level. It is anticipated that the choice of a smaller commensurate unit cell for the representation of the electronic structure will be useful for the study of epitaxial two-dimensional materials on various substrates in general.