Related papers: Dynamical Localization and Absolute Negative Condu…
It is shown that the excitation of charge carriers by ac electric field with zero average driving leads to a direct electric current in quantum well structures. The current emerges for both linear and circular polarization of the ac…
We propose a selfconsistent microscopic model of vertical sequential tunneling through a multi-quantum well.The model includes a detailed description of the contacts,uses the Transfer Hamiltonian for expressions of the current and it treats…
We have theoretically investigated the tunneling current induced by a terahertz (THz) field applied to an asymmetric double quantum well. The excitation couples an initially localized state to a nearby continuum of extended states. We have…
The current-voltage characteristics through a metallic quantum dot which is well coupled to a metallic lead are measured. It is shown that the I-V curves are composed of two contributions. One is a suppression of the tunneling conductivity…
Intense AC electric fields on semiconductor structures have been studied in photon-assisted tunneling experiments with magnetic field applied either parallel (B_par) or perpendicular (B_per) to the interfaces. We examine here the electron…
In this book article effects related to the vertical transport in weakly coupled multiple quantum wells are reviewed. A self-contained microscopical model for the calculation of the well-to-well currents without any fittings parameters is…
We investigate the dynamics of two interacting electrons moving in a one-dimensional array of quantum dots under the influence of an ac-field. We show that the system exhibits two distinct regimes of behavior, depending on the ratio of the…
We study conductance through a quantum dot under Coulomb blockade conditions in the presence of an external periodic perturbation. The stationary state is determined by the balance between the heating of the dot electrons by the…
The localization of two interacting electrons in a coupled-quantum-dots semiconductor structure is demonstrated through numerical calculations of the time evolution of the two-electron wave function including the Coulomb interaction between…
We study the dynamical transport in weakly coupled superlattices in the presence of intense radiation in the THz regime. We derive a general model for the time dependent tunneling current within the Keldysh nonequilibrium-Green-function…
We investigate sub-gap transport through a single-level quantum dot tunnel coupled to one superconducting and two normal-conducting leads. Despite the tendency of a large charging energy to suppress the equilibrium proximity effect, a…
We demonstrate that the nonlinear I-V characteristics of a two probe conductor is not an even function of magnetic field. While the conductance of a two-probe conductor is even in magnetic field, we find that already the contributions to…
A systematic study is made on the time-dependent dynamic transport characteristics of the side-coupled double quantum-impurity system based on the hierarchical equations of motion. It is found that the transport current behaves like a…
Various causes for negative differential conductance in transport through an interacting double quantum dot are investigated. Particular focus is given to the interplay between the renormalization of the energy levels due to the coupling to…
The Ohmic conductance and current through two quantum dots in series is investigated for the case of incoherent tunnelling. A generalised master equation is employed to include the discrete nature of the energy levels. Regions of negative…
We outline a generic ratchet mechanism for creating directed spin-polarized currents in ac-driven double well or double dot structures by employing resonant spin transfer through the system engineered by local external magnetic fields. We…
We present measurements of transport through two tunnel-coupled quantum dots of different sizes connected in series in a strong, variable, perpendicular magnetic field. Double dot conductance was measured both as a function of magnetic…
There have been many studies of the linear response ac conductance of a double barrier resonant tunneling structure (DBRTS). While these studies are important, they fail to self-consistently include the effect of time dependent charge…
We consider the transport and the noise characteristics for the case of a T-shape double quantum dot system using the equation of motion method. Our theoretical results, obtained in an approximation equivalent to the Hartree-Fock…
The Coulomb drag phenomenon in a Coulomb-coupled double quantum dot system is revisited with a simple model that highlights the importance of simultaneous tunneling of electrons. Previously, cotunneling effects on the drag current in…