Article

# Magnetic field effects on quantum ring excitons

Physical review. B, Condensed matter (Impact Factor: 3.66). 08/2000; DOI: 10.1103/PhysRevB.63.125302

Source: arXiv

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**ABSTRACT:**The transition energy, wave function and photoionization cross-section (PCS) in a Winternitz-Smorodinsky potential quantum ring (QR) with a donor impurity subjected to a uniform magnetic field along the z-axis have been investigated within the compact-density matrix approach. The dependence of these optical properties on the inner radius R1, the outer radius R2, and the magnetic field B is studied in detail. The results reveal that the transition energy, wave function and the PCS in a Winternitz-Smorodinsky potential QR have been strongly affected by these factors. In addition, it can be found that the resonant peak of the PCS presents the Aharonov-Bohm oscillation by changing the magnetic flux.Superlattices and Microstructures 10/2013; · 1.98 Impact Factor -
##### Article: Coupling effects on photoluminescence of exciton states in asymmetric quantum dot molecules.

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**ABSTRACT:**We present a theoretical study of photoluminescence from exciton states in InAs/GaAs asymmetric dot pairs, where interdot coupling is reached via magnetic field in the Faraday configuration. Electronic structure is obtained by finite element calculations, and Coulomb effects are included using a perturbative approach. According to our simulated spectra, bright excited states may become optically accessible at low temperatures in hybridization regimes where intermixing with the ground state is achieved. Our results show effective magnetic control on the energy, polarization and intensity of emitted light, and suggest these coupled nanostructures as relevant candidates for implementation of quantum optoelectronic devices.Nanoscale Research Letters 01/2014; 9(1):297. · 2.52 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**We consider a model of a quantum ring in the form of a thin layer, whose thickness increases linearly between inner and outer radii. We show that in the structural adiabatic limit, when the quantum ring thickness is much smaller than its lateral dimension, the wave equation for the electron confined in such structure can be completely separated. We use analytical solutions found for this model as the base functions for analyzing the effect of the structural non-homogeneity on the electronic spectrum and the Aharonov–Bohm oscillations of the energy levels, in the framework of the exact diagonalization method we found that the pattern of the electron's possible pathways in its displacements generated by the external magnetic field, forms a quasi-one-dimensional region along a guideline marked by a set of highest points of the crater. Therefore, the Aharonov–Bohm oscillations of the energy levels in a crater-shaped quantum dot without non-uniformities are similar to those in 1D quantum ring independently on the crater width. We show that a slight non-uniformity produced by a single valley and single mountain supresses the oscillations of several lower levels due to the localization of the corresponding rotational states close to the mountain. Nevertheless, when the non-uniformity becomes substantial due to the presence of multiple valleys and mountains, the rotational electron motion and the Aharonov–Bohm oscillations generated by the external magnetic field are restored, owing to the electron tunneling through mountains. We consider that our model of crater-shaped structure would be applicable in the analysis of a variety of more complicated problems related to systems of few carriers confined in nanostructures with ring-like geometry, as a starting point in the framework of the diagonalization method.Physica E Low-dimensional Systems and Nanostructures 02/2014; · 1.86 Impact Factor

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