Sergei Matinyan

Electron transfer between weakly coupled concentric quantum rings

The electronic structure of the semiconductor double concentric quantum nano-ring (DCQR) is studied under the single sub-band effective mass approach. We show that in the weakly coupled DCQR, that has been placed in transverse magnetic field, the electron spatial transition between the rings can occur due to electron level anti-crossing. The anti-crossing of the levels with different radial quantum numbers provides the conditions when the electron tunneling between rings becomes possible. Results of numerical simulation for the electron transition are presented for DCQRs of different geometry. In particular, the system of a QR with a QD located at center of this QR is considered.

Disappearance of quantum chaos in coupled chaotic quantum dots

Abstract Statistical properties of the single electron levels confined in the semiconductor (InAs/GaAs, Si/SiO 2 ) double quantum dots (DQDs) are considered. We demonstrate that in the electronically coupled chaotic quantum dots the chaos with its level repulsion disappears and the nearest neighbor level statistics becomes Poissonian. This result is discussed in the light of the recently predicted “huge conductance peak” by R.S. Whitney et al. [Phys. Rev. Lett. 102 (2009) 186802] in the mirror symmetric DQDs.

Si/SiO 2 Quantum Dots: Electronic Properties

Spherical shaped Si quantum dots (QDs) embedded into the SiO 2 substrate are considered in the single sub-band effective mass approach. The electron and heavy hole sub-bands are taken into account. The energy dependence of electron effective mass is applied especially for small size QD. Calculations of low-lying single electron and hole energy levels are performed. For QD of small sizes (diameter D ≤6 nm) there is a strong confinement regime when the number of energy levels is restricted to several levels. The first order of the perturbation theory is used to calculate neutral exciton recombination energy taking into account the Coulomb force between electron and heavy hole. The PL exciton data are reproduced well by our model calculations. We also compare the results with those obtained within model [1]. For weak confinement regime (size D ≥10 nm), when the number of confinement levels is limited by several hundred, we considered the statistical properties of the electron confinement. Distribution function for the electron levels is calculated and results are discussed.

To the theory of unstable states

Deviations of the decay law from exponents are discussing for a long time, however, experimental proofs of such deviations are absent. Here in the general form is shown that the conclusions about non-exponential contributions are due to the disregarding of advanced interactions, i.e. at principally non-relativistic considerations. We consider decay processes in the frame of interactions duration of the quantum field theory. We show that at this basis the usual exponential decay has place.