Noncircular semiconductor nanorings of types I and II: Emission kinetics in the excitonic Aharonov-Bohm effect

Grochol, M.; Zimmermann, R.

doi:10.1103/physrevb.76.195326

Cited by 21 publications

(12 citation statements)

References 53 publications

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“…The fact that a weak exciton disorder increases the observability of a coherent effect may be seen as counterintuitive, but the same effect has also been found in similar systems ͑e.g., in the exciton Aharonov-Bohm effect͒. 23,24 In the case of quantum well polaritons this result can also be obtained by using a coupled oscillator model. 25 We see in Fig.…”

Section: Resultsmentioning

confidence: 86%

Microcavity polaritons in disordered exciton lattices

Grochol

Piermarocchi

2008

Phys. Rev. B

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We investigate the interaction of excitons in a two dimensional lattice and photons in a planar cavity in the presence of disorder. The strong exciton-photon coupling is described in terms of polariton quasi-particles, which are scattered by a disorder potential. We consider three kinds of disorder: (a) inhomogeneous exciton energy, (b) inhomogeneous exciton-photon coupling and (c) deviations from an ideal lattice. These three types of disorder are characteristic of different physical systems, and their separate analysis gives insight on the competition between randomness and light-matter coupling. We consider conventional planar polariton structures (with excitons resonant to photon modes emitting normal to the cavity) and Bragg polariton structures, in which excitons in a lattice are resonant with photon modes at a finite angle satisfying the Bragg condition. We calculate the absorption spectra in the normal direction and at the Bragg angle by a direct diagonalization of the exciton-photon Hamiltonian. We found that in some cases weak disorder increases the light-matter coupling and leads to a larger polariton splitting. Moreover, we found that the coupling of excitons and photons is less sensitive to disorder of type (b) and (c). This suggests that polaritonic structures realized with impurities in a semiconductor or with atoms in optical lattices are good candidate for the observation of some of the Bragg polariton features.Comment: 8 pages, 5 figure

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Section: Resultsmentioning

confidence: 86%

Microcavity polaritons in disordered exciton lattices

Grochol

Piermarocchi

2008

Phys. Rev. B

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“…21,23,25 This discrepancy could be resolved if the disorder of the system and finite temperature were taken into account. [35][36][37] In our study we do not consider the disorder effect, which would modify our calculated results about the peak intensity of photoluminescence. On the other hand, our results about the peak position should not be changed qualitatively by the disorder.…”

Section: 25mentioning

confidence: 99%

Optical Aharonov-Bohm effect on Wigner molecules in type-II semiconductor quantum dots

2011

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We theoretically examine the magnetoluminescence from a trion and a biexciton in a type-II semiconductor quantum dot, in which holes are confined inside the quantum dot and electrons are in a ring-shaped region surrounding the quantum dot. First, we show that two electrons in the trion and biexciton are strongly correlated to each other, forming a Wigner molecule: Since the relative motion of electrons is frozen, they behave as a composite particle whose mass and charge are twice those of a single electron. As a result, the energy of the trion and biexciton oscillates as a function of magnetic field with half the period of the single-electron Aharonov-Bohm oscillation. Next, we evaluate the photoluminescence. Both the peak position and peak height change discontinuously at the transition of the many-body ground state, implying a possible observation of the Wigner molecule by the optical experiment.

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“…In this work we find a mechanism for controlling excitonic lifetimes in a single Aharonov-Bohm (AB) nanoring, again by the use of a constant electric field. Suppression of ground state exciton emission has already been seen for polarised excitons in the ring geometry for particular magnetic field strengths [15]; the introduction of impurities [16,17] and the use of slightly eccentric rings [18] makes previously dark states become optically active. In the present system, recombination of the electronhole pair is not prevented by their confinement to different nanostructures, as previously seen, but by appropriate tuning of external magnetic and electric fields.…”

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confidence: 99%