Transport in weak barrier superlattices and the problem of the terahertz Bloch oscillator

Transport in narrow minigap superlattices and the terahertz Bloch oscillator

“…The NDC in this case is due to 'lasing without population inversion'. The frequency dependence of the differential conductivity in this case (NDC below or above the Bloch frequency) depends (as quasi-classical calculations [5,17] show) on the type of Wannier-Stark level broadening (see [18,19]).…”

Dynamic chaotisation of the electronic subsystem in a graphene superlattice subjected to the electromagnetic radiation

“…(15) Note that if λ = 0 then from ( 13) and ( 15) the result [48,49] is obtained. It can be seen from formula (15) that if the frequency Ω approaches the value:…”

“…The quasi-classical theory of the nonlinear EM response of graphene was developed in [3,8,13,14], where the possible applications of graphene structures for the generation of terahertz (THz) radiation were discussed. Because the superlattice (SL) is a suitable material for the working medium of generators of THz EM radiation [15][16][17][18] the electronic properties of graphene SL (GSL) are also under very intensive study [18][19][20][21][22][23][24][25][26][27][28].…”

Effect of a bichromatic electric field on the current-voltage characteristic of a graphene-based superlattice

“…It was shown in [13] that, in the vicinity of the Dirac point, the energy of electron motion along the GSL axis is a periodic function of the electron momentum in this direction. In addition, the extra SL potential in graphene is of interest in the context of the so called Bloch oscillator problem [14,15]. Therefore, studies of the absorption of terahertz electromagnetic (EM) radiation and the effect of high frequency fields on the current-voltage (I-V) characteristic of GSLs are rather urgent.…”