Coherent Resonant Tunneling Model in Double-Barrier Nanostructures

We propose a coherent resonant tunneling model in double-barrier nanostructutes in which besides an interference effect originated from coherent tunneling of single electron through two barriers, the effects of one-electron charging, discrete energy spectrum and electron interactions between barriers are also important. The interference effect, like that for light in Fabry-Perot cavity, will occur no matter whether a magnetic field exists or not, and is shown to have significant effect on the systems' tunneling current. Our model agrees
surprisingly well with all the main experimental features of the phenomenon discovered by Scott Thomas et al.     

Phonon-Assisted Tunneling Current in a Double-Barrier Heterostructure with a Quantum Well

Journal of Russian Laser Research - Based on a quantum-mechanical model with a non-Hermitian Hamiltonian, we theoretically describe the tunneling current in a heterostructure containing a quantum...     

The Effects of the Self-Consistent Field of Electrons and Γ–X-Intervalley Scattering on Resonant Tunneling in Double-Barrier Structures

The self-consistent electron field approximation is used to calculate the current-voltage characteristics and electron-transmission and tunneling-time spectra in GaAs/AlAs (001) semiconductor heterostructures within the three-valley effective-mass model and to study the effect of the composite band spectrum of GaAs and AlAs materials.     

An Analysis of Resonant Magnetotunneling in the Double-Barrier Heterostructure

We study resonant magnetotunneling in the double-barrier heterostructure in the sequential tunneling picture. The effects arising from charge buildup in the well are considered by assuming that the quasibound energy in the well varies linearly with the applied bias. Under appropriate approximations, the tunneling current density and the corresponding differential conductance are derived analytically. The results for the peak positions in differential conductance and the threshold current position are consistent with experiments.     

Resonant Photon-Assisted Tunneling Through a Coupled Double-Quantum-Dot System

An analytical formula of the tunneling current through a coupled double-quantumdot system in the presence of a time-dependent electric field is obtained by using the Keldysh nonequilibrium Green's function technique. The dependence of the time-averaged current on the frequency of the electric field, as well as the dependence of the multiphoton assisted tunneling on the strength of the electric field are studied. The features of I-V_dc characteristic are also investigated. Besides, we present a simplified formula which can be used to determine the heights of the resonant peaks conveniently.     

Dissipative Effects on Resonant Tunneling

The resonant tunneling of a particle coupled with a set of local bosons can be mapped onto the single-site model in an appropriate time scale. In this paper we investigate the process of the particle through a barrier associated with the dissipative source. The frequency and temperature-dependent tunneling probability has been evaluated explicitly in the spirit of independent boson assumption by using golden rule for transition rate. The character of sideband structure is revealed and the tunneling current with dissipation is also given.     

Electron Transport in Graphene-Based Double-Barrier Structure under a Time Periodic Field

The transport property of electron through graphene-based double-barrier under a time periodic field is investigated. We study the influence of the system parameters and external field strength on the transmission probability. The results show that transmission exhibits various kinds of behavior with the change of parameters due to its angular anisotropy. One could control the values of transmission and conductivity as well as their distribution in each
band by tuning the parameters.     

结构和磁场对三势垒结构中共振隧穿时间的影响

为了理解在三势垒结构中准束缚能级Ez和隧穿寿命对磁场的依赖性,采用传输矩阵的方法研究了在三势垒结构中的共振隧穿过程。分别研究了在三势垒结构中的透射几率特征和隧穿寿命。结果表明:随着中间势垒厚度L的增加,第一准束缚能级E1z增加,而第二准束缚能级E2z却减小。随着磁场强度B和朗道量子数n的增加,与第一和第二准束缚能级(E1z,E2z)对应的寿命τ缩短。对于B=15和n=15的情况,L对τ的影响很小。     

Resonant Tunneling Through a Quantum Dot in the presence of Alternating Fields

We have derived an analytical expression of the transmission probability through a quantum dot under an alternating field by using the nonequilibrium Green function techniques. The calculation. results show a simultaneously quenching in all side bands which are reported by Wagner recently. In addition, the theory of Jauho et al. has been applied to accounting for the latest experiments by Kouwenhoven et al. The mechanism leading to the zero bias current and its sign change is attributed to the photon-assisted-tunneling process.     

Complex-Domain Semiclassical Theory: Application to Time-Dependent Barrier Tunneling Problems

Semiclassical theory based upon complexified classical mechanics is developed for periodically time-dependent scattering systems, which are minimal models of multi-dimensional systems. Semiclassical expression of the wave-matrix is derived, which is represented as the sum of the contributions from classical trajectories, where all the dynamical variables as well as the time are extended to the complex-domain. The semiclassical expression is examined by a periodically perturbed 1D barrier system and an excellent agreement with the fully quantum result is confirmed. In a stronger perturbation regime, the tunneling component of the wave-matrix exhibits a remarkable interference fringes, which is clarified by the semiclassical theory as an interference among multiple complex tunneling trajectories. It turns out that such a peculiar behavior is the manifestation of an intrinsic multi-dimensional effect closely related to a singular movement of singularities possessed by the complex classical trajectories.     

On Times and Speeds of Time-Dependent Quantum and Electromagnetic Tunneling

Journal of Experimental and Theoretical Physics - This is a review of studies of quantum tunneling, which is described by the one-dimensional Schrödinger equation, and electromagnetic...     

Quantum Tunneling in Time-Dependent Potential Barrier: a General Formulation and Some Exactly Solvable Models

Quantum tunneling in one spatial dimension in the presence of time-dependent potentials is investigated theoretically. First, a general multichannel formulation of the problem is given for harmonic time-dependence. The case of an oscillatory delta-function potential of constant strength is discussed at length and specific numerical calculations are presented for the reflection and transmission coefficients. Then other exactly solvable time-dependent potentials are obtained by carrying out successive unitary transformations. As an example of this class, a delta-function potential with time-dependent strength and boundary conditions is studied. Finally tunneling time-delay for time-dependent potentials is formulated in the multichannel situation, and also the concept of first passage time for the decay of a wave packet confined to one well of a double well potential is generalized for the case of time-dependent barrier and boundary conditions.     

电子横向运动对共振隧穿的影响

讨论了电子横纵方向运动耦合时的隧穿现象,对CdSe/Zn1-xCdxSe方形双势垒结构和抛物形双势垒结构的数值计算表明,在零偏压和非零偏压情况下,电子横向运动对共振隧穿的影响是不容忽略的。     

Observation of Resonant Photon Tunneling in Photonic Double Barrier Structures

Reflectance and transmittance of 632.8 nm He-Ne laser light for photonic double barrier structures (consisting of a SF10 prism, SiO₂ layer, Al or Al₂O₃ active layer, SiO₂ layer and SF10 prism) were measured as a function of the angle of incidence for both the ρ- and s-polarized incidence. Sharp reflection dips and transmission peaks were observed at angles larger than the critical angle of total reflection. The appearance of the transmission peaks can be attributed to resonant photon tunneling through the photonic double barrier structures analogous to resonant electron tunneling through double potential barrier structures. Resonant tunneling is mediated by the long-range surface plasmon polariton in the case of the Al active layer and the electromagnetic guided modes in the case of the Al₂O₃ layer.This paper was originally presented at the seventh Meeting on Near Field Optics, which was held on July 1, 1998 at Nagoya University, Nagoya, organized by Research Group on Near Field Optics, the Optical Society of Japan, an affiliate of Japan Society of Applied Physics. The authors have won the Near Field Optics Award for their best presentation at the meeting.