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L. Besombes et al. , PRL 93 , 207403, 2004

Single exciton spectroscopy in a semimagnetic nanocrystal J. Fernández-Rossier Institute of Materials Science, University of Alicante, SPAIN. CdTe nanocrystal+ 1Mn. CdTe nanocrystal. PL. PL. S=5/2 2S+1=6. L. Besombes et al. , PRL 93 , 207403, 2004. Spin relaxation. Absorption.

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L. Besombes et al. , PRL 93 , 207403, 2004

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  1. Single exciton spectroscopy in a semimagnetic nanocrystalJ. Fernández-RossierInstitute of Materials Science, University of Alicante, SPAIN CdTe nanocrystal+ 1Mn CdTe nanocrystal PL PL S=5/2 2S+1=6 L. Besombes et al., PRL93, 207403, 2004 Spin relaxation Absorption Emission 6NMn Goal: Calculate PL and quantum information Talk available in: www.ua.es/jfrossier/personal

  2. 4x6N 4 -1 -1 +1 +2 Exciton States Manifold (XSM) 6N 1 Ground State Manifold (GSM) • Method : • Calculation of one-body wave functions (for a given dot) • Evaluation of many body exciton-Mn spin Hamiltonian • Exact diagonalization of GSM • Exact diagonalization of XSM • Linear reponse theory

  3. FORMALISM Ground State Manifold (GSM) 6N Exciton States Manifold (XSM) e Heisenberg 4 6N Ising h SPIN ORBIT INTERACTION

  4. Valence band Spin orbit: Ising coupling SHAPE MATTERS: Quenching of transverse Hole-Mn exchange

  5. GSM and XSM spectrum Magnetic Field (0,0,5) 1 Mn NG=6 NX=24 2 Mn NG=36 NX=244 3Mn NG=216 NX=864 E(meV) E(meV)

  6. PL: results Photoluminescence(PL)Theory PL, theory PL, experiment Spontaneous Emission from X to G Energy conservation Optical Selection rules SPIN BLOCKADE PL SPECTRUM Energy (meV) Occupation of excited state Thermal like occupation

  7. OPTICAL SPIN BLOCKADE Standardoptical selection rule Franck Condon= Spin Blockade 24*6=144 XSM to GSM Only 12 are allowed GSM Photon measurement= SPIN MEASUREMENT XSM

  8. N=3. Narrowing and shift PL, experiment 0T 2T 4T 6T 8T 10T P. S. Dorozhkin, Phys. Rev. B 68, 195313 (2003)

  9. Conclusions • Model Hamiltonian gives good account of PL experiments: • Single Mn • Broadening and narrowing of lines • Voigt wider than Faraday • Optical detection of quantum state of N=1,..4 spin S=5/2 in semiconductor nanocrystal. • Related papers: • JFR, in preparation • JFR, L. Brey, Phys. Rev. Lett. 93 117201 (2004) • G. Chiappe, JFR, et al, Condmat/0407639

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