Observation of “Partial Coherence” in an Aharonov-Bohm Interferometer with a Quantum Dot

Abstract

We report experiments on the interference through spin states of electrons in a quantum dot (QD) embedded in an Aharonov-Bohm (AB) interferometer. We have picked up a spin-pair state, for which the environmental conditions are ideally similar. The AB amplitude is traced in a range of gate voltage that covers the pair. The behavior of the asymmetry in the amplitude around the two Coulomb peaks agrees with the theoretical prediction that the spin-flip process in a QD is related to the quantum dephasing of electrons. These results constitute evidence of "partial coherence" due to an entanglement of spins in the QD and in the interferometer.

Comment on “Do Intradot Electron-Electron Interactions Induce Dephasing?”

“…Likewise, they claim that the theoretically predicted [2] and experimentally verified [3] asymmetry of the Aharonov-Bohm oscillation amplitude is not associated with dephasing. In this Comment, we point out severe inconsistencies in the analysis of Ref.…”

Formation of nonequilibrium steady states in interacting double quantum dots: When coherences dominate the charge distribution

“…Only recently, we have given a detailed study of the steady-state properties of the systems SERIAL and BRANCHED (cf. [ 17,18,51,92,93,121]. These models have also been used to describe (linear or branched)…”

“…Such a system can be realized by an array of quantum dots arranged to form an AharonovBohm interferometer [17,18,92,93] or a nanoscale molecular conductor with an appropriate level structure [94][95][96][97][98][99][100][101][102][103]. The spinless situation may be realized physically if the spin degeneracy is lifted by an external magnetic field or by spin-polarized electrodes.…”

Transient probing of the symmetry and the asymmetry of electron interference

“…31 With a QD sitting on one arm, making the other arm of the ring as a reference, studies on the resonant tunneling through the QD have been experimentally carried out. [32][33][34][35][36][37][38][39] Ring-shaped natural molecules and artificial molecules are useful nanostructures that can host the AB effect and at the same time provide manipulable geometric symmetry. For ring-shaped natural molecules, effective use of magnetic fluxes either requires unrealistically high magnetic fields 40 or other special conditions.…”

“…The currents on the left and on the right differ, besides the overall factor Γ α in Eq. (39), only by the factor Γ α + Γᾱ cos φ in the amplitude in front of the oscillating term sin (ε g (φ) t). Applying Γ L ≪ Γ R to Eq.…”