Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 15: Focussed Session: Geometry- and Topology-Controlled Nanoarchitectures I
HL 15.7: Vortrag
Dienstag, 13. März 2018, 11:30–11:45, EW 015
Voltage tuning of exciton topology and g-factor in type-II InAs/GaAsSb quantum dots — •Benito Alén1, José M. Llorens1, Edson R. Cardozo de Oliveira2, Lukasz Wevior1, Vivaldo Lopes-Oliveira3, Victor López-Richard2, José M. Ulloa4, Marcio D. Teodoro2, Gilmar E. Marques2, Alberto García-Cristóbal5, and Guo-Quiang Hai3 — 1IMN-Instituto de Micro y Nanotecnología (CNM-CSIC), Spain. — 2Dept. de Física, Universidade Federal de Sao Carlos, Brazil. — 3Instituto de Física, Universidade de Sao Paulo, Brazil. — 4ISOM, Universidad Politécnica de Madrid, Spain. — 5ICMUV, Universidad de Valencia, Spain.
We will 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 direction thus allows large tuning of the radiative lifetime. [1] It also brings a topological change in the hole ground state wavefunction from singly to doubly connected. [1,2] 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 k.p and effective Hamiltonian models. This result could open a venue for new quantum memories beyond the InAs/GaAs realm.
[1] J. M. Llorens et al. Appl. Phys. Lett., 107, 183101 (2015) [2] J. M. Llorens et al. arXiv:1710.08828 [cond-mat.mes-hall]