Light-Controlled Optical Aharonov-Bohm Oscillations in a Single GaAs/AlGaAs Quantum Ring
摘要
The optical Aharonov-Bohm effect in a quantum ring was investigated in terms of magnetic field dependence of excitons and biexcitons. The fine exciton states of quantized orbital angular momentum in a quantum ring were considered theoretically, and the presence of quantum beats was predicted as evidence of the quantum coherence of the fine exciton states. In the case of GaAs/GaAlAs quantum rings grown by the droplet epitaxy, we found various disorder effects are associated such as structure anisotropy, localization, and internal electric field, resulting in a modulation of the oscillation periods. Additionally, we found that a strongly correlated exciton pair can be formed in a single quantum ring similar to the Wigner molecule. In this case, the biexciton emission energy changes abruptly at transition magnetic fields with a fractional oscillation period compared to that of the exciton, the so-called fractional optical Aharonov-Bohm oscillations.