Electron transmission through a periodically driven graphene magnetic barrier

Abstract

The kinetic transport of electrons through graphene magnetic barriers is studied theoretically in presence of an external time harmonic scalar potential. The transmission coefficients are calculated in the framework of the non-perturbative Floquet theory using transfer matrix method. The time dependent scalar potential is found to suppress the usual Fabry-Perot oscillations occurring in the transmission through a constant vector potential barrier (corresponding to two oppositely directed δ-function magnetic barriers). Two types of asymmetric Fano resonances (FR) are noted and are discussed for the narrow barrier structure. One of them arises due to the oscillatory mode while the other due to the evanescent mode of the electron wave inside the barrier. In contrast, the oscillating field favours the transmission for rectangular magnetic barrier structure and also exhibits the FR due to the presence of bound state inside the barrier. The characteristic Fano line shape can be tuned by varying the amplitude of the oscillating potential. The detection of such FRs' offers an efficient tool for the identification of the quasi-bound and evanescent extended states inside the barrier not reported in the literature so far, for the case of graphene magnetic barrier structures.

Quenching effect of oscillating potential on anisotropic resonant transmission through a phosphorene electrostatic barrier

“…Following our earlier work [36,37] the function 𝜒 𝑥, 𝑦, 𝑡 can be written as 𝜒 𝑥, 𝑦, 𝑡 = 𝑒 −𝑖 𝐸 𝑋 −𝐸 𝐹 𝑡/ℏ 𝑒 −𝑖𝛼𝑆𝑖𝑛 𝜔𝑡 𝜑 𝑥, 𝑦…”

“…Following our earlier work 37 , 38 the function can be written as with . The time periodicity of leads to the parameter , being an integer.…”

Nearly pure spin-valley sideband tunneling in silicene: Effect of interplay of time periodic potential barrier and spin-valley-dependent Dirac mass

“…In the low energy limit, the carriers in silicene may be described by the massive relativistic behavior. In the absence of time periodic potential and external forces for xL  , the wave function may obey the massive Dirac equation given by [12,[15][16][17][21][22][23][24][25][26][27][28] In the TP-region for xL  , the influence of time periodic potential 01 V(t) V V cos t = +  [30][31][32][34][35][36]38,39,41,42] and the external fields are taken into account for photon creation and spin-valley-dependent gap opening, respectively. The motion of electron may be described using the wave equation of the form being buckling parameter is generated due to its buckled atomic structure [13][14][15].…”

“…Electron with energy E is injected into the barrier and then leaves the barrier with the energy of E ( )n + −  (n=0,1,2,...) due to absorbing (emitting) n-photons [38,43]. The tunneling through time periodic potential in graphene shows the transmission oscillating due to Klein tunneling and coupling with photon in case of massless fermions [30,31,[34][35][36][37][38]40,41]. The Klein tunneling was suppressed by the irradiation of a strong laser field [33,37,40].…”

Electron Transmission Across Normal Metal-Strained Graphene-Normal Metal Junctions

“…In recent decades, the theoretical and experimental studies on graphene quantum wells (including p-n junctions) 13,14,21,27 , superlattices 16,17,24 and graphene quantum dots [35][36][37] have been carried out by many groups. Most of the studies focused on the graphene-graphene heterostructures, whose different segments are tuned by the different magnetic fields (vector potentials) 15,17,24,28 and different electric potentials to create wells and barriers 13,17 , while the confinement potentials for graphene quantum dots are vector potentials 38 as well as static and time-dependent electrical potentials 25,36 in different circular regions; as for hybrid graphene heterostructures, there are graphene-metal heterostructures [39][40][41][42][43][44] and graphene-superconductor heterostructures where the proximity of graphene to superconducting layer result in the specular Andreev reflections [45][46][47] .…”