Resonances in transmission through an oscillating barrier

Resonant second-harmonic generation in a ballistic graphene transistor with an ac-driven gate

“…This leads to a Fano resonance in direct transmission, as recently found numerically [23][24][25]. Analogous Fano resonances were earlier studied [26] for few-channel waveguides in 2DEGs with attractive point scatterers (for a review of Fano resonances in nanostructures, see Ref. [30]).…”

“…This dynamic Stark shift can be investigated quantitatively by computing the determinant of the matrix M s defined in Including drive, Z 1 > 0, the zeros of the determinant move into the complex energy plane [26,38], E b → E zero , signaling a quasibound state. The resonance energy E r = Re(E zero ) is then shifted from E b .…”

“…In theoretical investigations for low doping (Fermi energy E F close to the Dirac point) and high frequencies , with E F and of comparable magnitude (we put = 1), a true quantum mechanical description becomes necessary. For time-dependent transport in two-dimensional electron gases (2DEGs) in semiconducting heterostructures, displaying a quadratic dispersion relation, photon-assisted tunneling in time-harmonic potentials is described well within a Floquet theory framework and have been investigated for a long time [26][27][28][29]. Here, we study theoretically a ballistic field effect transistor with a harmonic drive applied to the top gate, see Fig.…”

Transmission properties of the oscillating δ-function potential

“…of functions of the incident energy and the strength of the delta potential. This is a considerable advantage over the numerical computation of the transmission done before using this kind of potential [7,8]. Our expression allows us to study with greater detail, both analytically and numerically, several different features of the transmission that had not been noticed or explained before, such as the location of the zero-pole resonances of the transmission and the almost periodic behavior of their position, the existence of non-resonant "bands", the dependence of the pole residues on energy and the existence of the so-called (in the language of nuclear physics) "threshold anomalies" in the transmission.…”

“…Time-dependent potentials in mesoscopic systems have been studied for a number of years in connection with electron-phonon interactions [1], quantum tunneling time [2,3,4], ionization [5,6], electronic transmission [7,8,9,10] and also in the field of quantum chaos [11]. One of the interesting features of localized time-periodic potentials is the presence of resonances or quasi-bound "states", which could be thought of as electrons dynamically trapped by the oscillating potential.…”