5 years ago

Electrically tunable exciton topology and $g$-factor in type-II InAs/GaAsSb quantum dots.

A. García-Cristóbal, M. D. Teodoro, J. M. Llorens, V. López-Richard, J. M. Ulloa, G. Quiang-Hai, G. E. Marques, V. Lopes-Oliveira, L. Wevior, E. R. Cardozo de Oliveira, B. Alén

We report experimental and theoretical work done in the InAs/GaAsSb QD system. For Sb molar fractions beyond 16 %, the band alignment becomes type II, with the electron confined inside the InAs and the hole delocalized in the GaAsSb overlayer. Voltage control of the exciton dipole moment in the vertical and lateral directions thus allows a topological change in the exciton ground state wavefunction from singly to doubly connected. The latter causes Aharonov-Bohm oscillations and a change of the exciton g-factor, as observed in the QD ensemble magneto-photoluminescence. Both effects are modulated by external bias in a device and can be explained in the frame of $\mathbf{k}\cdot\mathbf{p}$ and effective Hamiltonian models. These results could open a venue for new quantum memories beyond the InAs/GaAs realm.

Publisher URL: http://arxiv.org/abs/1710.08828

DOI: arXiv:1710.08828v4

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