Peculiar optical properties of bilayer silicene under the influence of external electric and magnetic fields

Abstract

We conduct a comprehensive investigation of the effect of an applied electric field on the optical and magneto-optical absorption spectra for AB-bt (bottom-top) bilayer silicene. The generalized tight-binding model in conjunction with the Kubo formula is efficiently employed in the numerical calculations. The electronic and optical properties are greatly diversified by the buckled lattice structure, stacking configuration, intralayer and interlayer hopping interactions, spin-orbital couplings, as well as the electric and magnetic fields ( ). An electric field induces spin-split electronic states, a semiconductor-metal phase transitions and the Dirac cone formations in different valleys, leading to the special absorption features. The Ez-dependent low-lying Landau levels possess lower degeneracy, valley-created localization centers, peculiar distributions of quantum numbers, well-behaved and abnormal energy spectra in Bz-dependencies, and the absence of anti-crossing behavior. Consequently, the specific magneto-optical selection rules exist for diverse excitation categories under certain critical electric fields. The optical gaps are reduced as Ez is increased, but enhanced by Bz, in which the threshold channel might dramatically change in the former case. These characteristics are in sharp contrast with those for layered graphene.

Atomistic Band-Structure Computation for Investigating Coulomb Dephasing and Impurity Scattering Rates of Electrons in Graphene

“…In recent years, by using the low-energy Dirac Hamiltonian [ 4 ], we have extensively explored varieties of dynamical properties of electrons in graphene and other two-dimensional materials, including Landau quantization [ 18 , 31 , 32 , 33 , 34 , 35 ], many-body optical effects [ 36 , 37 , 38 , 39 , 40 , 41 ], band and tunneling transports [ 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ], etc. In this paper, we particularly focus on the application of computed electronic states and band structures from a tight-binding model to the calculations of Coulomb and impurity scatterings of electrons in graphene on the basis of a many-body theory [ 3 , 4 ], where the former and latter determine the lineshape [ 1 ] of an absorption peak and the transport mobility [ 44 ], respectively.…”

“…k = f h k = 1/2 at the K valley or k = 0. Here, the calculated CDD rates from Equations(34) and(40), respectively, for electrons ∆ e (k) and holes ∆ h (k) are presented in Figure9aat T = 77 K and in Figure9bat T = 300 K. Since f e,h k ∼ exp(−ε e,h k /k B T) as ε e,h k k B T, the thermal occupations of electron and hole states will be limited mostly to wave numbers close to the K valley due to their lower kinetic energies ε e,h k around k = 0, as seen in Figure6. The Coulomb diagonal-dephasing rates ∆ e,h (k) presented in Figure9a,b quantifies an amplitude-decay process of induced electron-hole optical coherence with wave vector k by an optical field towards the state before external perturbation.…”

Role of interlayer spacing on electronic, thermal and optical properties of BN-codoped bilayer graphene:\break Influence of the interlayer and the induced dipole-dipole interactions

“…For instance, the electronic bandgap of BLG can be tuned via foreign dopant atoms or electric field that break the sub-lattice symmetry [4,5]. Consequently, the bandgap induces good thermal and optical properties of the system [6,7]. This has led to interest in BLG in photonics and optoelectronics, presented by its strong application possibilities ranging from solar cells and light-emitting devices to touch screens, photo-detectors and ultrafast lasers [8,9].…”

Outstanding Tunable Electrical And Optical Characteristics In Monolayer Silicene At high Terahertz Frequencies

“…Also in [35] have been worked on the optical properties of silicene nanoribbons and the effect of an external field on them. Other articles have investigated the optical properties of silicene [36][37][38][39]. In this paper, we explore the optical properties of silicene such as optical conductivity and refractive index under the influence of environmental factors such as temperature, Fermi level, EF, and perpendicular external electric field, Ez to it.…”