Coulomb-Modified Fano Resonance in a One-Lead Quantum Dot

We study the Coulomb blockade of tunneling through a double quantum dot. The temperature dependence of the linear conductance is strongly affected by the inter-dot tunneling. As the tunneling grows, a crossover from temperature-independent peak conductance to a power-law suppression of conductance at low temperatures is predicted. This suppression is a manifestation of the Anderson orthogonality catastrophe associated with the charge re-distribution between the dots, which ac...

In this paper, we investigate transient quantum transport in a nanoscale Aharonov-Bohm (AB) interferometer consisting of a laterally coupled double quantum dot (DQD) coupled to the source and drain electrodes. The transient linear conductance is derived at finite temperature of the leads, and is divided into three terms contributed from different transport channels. By observing the transient linear conductance and time evolution of the elements of the reduced density matrix ...

The charging energy of a quantum dot is measured through the effect of its potential on the conductance of a second dot. This technique allows a measurement of the scaling of the dot's charging energy with the conductance of the tunnel barriers leading to the dot. We find that the charging energy scales quadratically with the reflection probability of the barriers. In a second experiment we study the transition from a single to a double-dot which exhibits a scaling behavior l...

We study theoretically a quantum dot in the quantum Hall regime that is strongly coupled to a single lead via a point contact. We find that even when the transmission through the point contact is perfect, important features of the Coulomb blockade persist. In particular, the tunneling into the dot via a second weakly coupled lead is suppressed, and shows features which can be ascribed to elastic or inelastic cotunneling through the dot. When there is weak backscattering at th...

The transmission probability and phase through a few-electron quantum dot are studied within a resonance theory for the strong coupling regime to the conducting leads. We find that the interaction between overlapping resonances leads to their separation in the complex energy plane and to the decoherent dephasing of the resonant modes. The appearance of the Fano effect is conditioned not only by the induced dephasing generally associated with a phase lapse, but also by a favor...

We analyze the influence of a local pairing on the quantum interference in nanoscopic systems. As a model system we choose the double quantum dot coupled to one metallic and one superconducting electrode in the T-shape geometry. The analysis is particularly valuable for systems containing coupled objects with considerably different broadening of energy levels. In such systems, the scattering of itinerant electrons on a discrete (or narrow) energy level gives rise to the Fano-...

We investigate the electronic transport in a quantum wire with localized Rashba interaction. The Rashba field forms quasi-bound states which couple to the continuum states with an opposite spin direction. The presence of this Rashba dot causes Fano-like antiresonances and dips in the wire's linear conductance. The Fano lineshape arises from the interference between the direct transmission channel along the wire and the hopping through the Rashba dot. Due to the confinement, w...

We study the electronic transport through a double quantum dot molecule attached to leads, and examine the transition from a configuration in series to a symmetrical parallel geometry. We find that a progressive reduction of the tunneling through the antibonding state takes place as a result of the destructive quantum interference between the different pathways through the molecule. The Fano resonance narrows down, disappearing entirely when the configuration is totally symme...

We investigate low-temperature transport characteristics of a side-coupled double quantum dot where only one of the dots is directly connected to the leads. We observe Fano resonances, which arise from interference between discrete levels in one dot and the Kondo effect, or cotunneling in general, in the other dot, playing the role of a continuum. The Kondo resonance is partially suppressed by destructive Fano interference, reflecting novel Fano-Kondo competition. We also pre...

Transient electron dynamics and the Fano resonance formation over time in transport through a two quantum dot system in a T-shape geometry (2QD-T) are analysed for free electrons. Time evolution of the transport characteristics are different for a weak and a strong inter-dot coupling with respect to the dot-electrode coupling. When the dot-dot coupling is weak, we find that transport dynamics is governed by two channel tunneling processes with two different relaxation times a...