Silicene As Spin Filter And Spin Separator

Using the molecular epitaxial method, Vogy et al. achieved silicene grown on the Ag(111) substrate in2012. Silicene have attracted extensively attention because of its2dimension honeycomb structure and unique physical properties. The large spin-orbit coupling(SOC) of silicene ascribed to the buckled structure make it to be hopeful to realize the topological insulator and ideal material for spintronic devices in the future.In this thesis, we introduce the experimental progress and theoretical results of silicene. Based on the novel physical properties, spin transport properties of spin-separate devices about silicene have been analyzed and discussed by numer-ical calculation.In the first chapter, the experimental progress and theoretical results related to geometry structure and physical properties of silicene were introduced. Be-sides, the low-energy four-band effective Hamiltonian of silicene was presented with symmetry considerations of silicene structure and first-principles calcula-tion. By tight-binding method, the electronic structure of various silicene phases have been studied. Combining with the application of electric field Ez to control the gap of the energy band and the exchange field M to induce the spin-split of electronic structure, the interesting phase of silicene, such as quantum anomalous Hall (QAH) insulator, valley polarized metal (VPM), marginal valley polarized metal (M-VPM), quantum spin Hall insulator and band insulator, will appear.In the second chapter, from Drude formula, the localization condition of weak scattering theory has been derived. There also exist Anderson location theory of disorder system and the condition of Anderson disorder model. The end, the development of Anderson transition, random disorder, bond disorder and Anderson topological insulator are shown.In the last chapter, spin transport properties of spin-separate devices about silicene have been analyzed and discussed systematically by numerical calcula-tion.