A light-hole exciton ground state in semiconductor quantum dots : fabrication and fine structure
Vendredi 20 septembre 2013 10:30
- Duree : 1 heure
Lieu : Room MD-1-21, ESRF - 6 Rue Jules Horowitz - Grenoble
Orateur : Yongheng HUO (Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden, Germany)
A light-hole exciton is a quasi-particle formed from a single electron bound to a single light-hole (LH). This type of fundamental excitation, if confined inside a semiconductor quantum dot (QD), could be advantageous in quantum information science and technology1-4 compared with heavy-hole (HH) exciton. These include the coherent conversion of photons into electron-spins1, the possibility to directly control the LH spin state via microwaves2, the direct tomographic measurement of the electron spin state or spin coherence3, and the faster and more stable control of a magnetic impurity spin coupled to a QD4. However, because confinement and strain in conventional QDs favor a ground-state single-particle hole with dominant HH character, LH has been neglected so far. Here we demonstrate the creation of a LH exciton ground state by applying elastic stress to an initially unstrained QD via moleculare beam epitaxy (MBE). Its signature is clearly distinct from that of the well-known HH exciton and consists of three orthogonally-polarized bright optical transitions and a fine-structure splitting of hundreds of μeV between in-plane and out-of-plane components. This work paves the way for the exploration of the fundamental properties and of the potential relevance of three-dimensionally confined LH states in quantum technologies.
1. R. Vrijen & E. Yablonovitch, Physica E 10, 569-575 (2001).
2. D. Sleiter & W. F. Brinkman, Phys. Rev. B 74, 153312 (2006).
3. H. Kosaka, et al., Nature 457, 702-705 (2009).
4. D. Reiter, T. Kuhn & V. M. Axt, Phys. Rev. B 83, 155322 (2011
Contact : claudine.romero@esrf.fr
Discipline évènement : (Physique)
Entité organisatrice : (ESRF)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire ESRF)
Site de l'évènement : Polygone scientifique
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