Quantum oscillations in magnetically doped colloidal nanocrystals

Abstract

Progress in the synthesis of colloidal quantum dots has recently provided access to entirely new forms of diluted magnetic semiconductors1, some of which may find use in quantum computation2,3,4,5,6. The usefulness of a spin qubit is defined by its Rabi frequency, which determines the operation time, and its coherence time, which sets the error correction window7. However, the spin dynamics of magnetic impurity ions in colloidal doped quantum dots remain entirely unexplored. Here, we use pulsed electron paramagnetic resonance spectroscopy to demonstrate long spin coherence times of 0.9 µs in colloidal ZnO quantum dots containing the paramagnetic dopant Mn2+, as well as Rabi oscillations with frequencies ranging between 2 and 20 MHz depending on microwave power. We also observe electron spin echo envelope modulations of the Mn2+ signal due to hyperfine coupling with protons outside the quantum dots, a situation unique to the colloidal form of quantum dots, and not observed to date.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: Characteristics of colloidal Zn0.9995Mn0.0005O QDs.
Figure 2: Rabi oscillations.
Figure 3: Echo decay and ESEEM.

References

  1. 1

    Beaulac, R., Ochsenbein, S. T. & Gamelin, D. R., Colloidal transition-metal-doped quantum dots, in Nanocrystal Quantum Dots: Synthesis and Electronic and Optical Properties, 2nd edn (ed. Klimov, V. I.) (Taylor & Francis, 2010).

    Google Scholar 

  2. 2

    Loss, D. & DiVincenzo, D. P. Quantum computation with quantum dots. Phys. Rev. A 57, 120–126 (1998).

    CAS  Article  Google Scholar 

  3. 3

    Engel, H-A., Recher, P. & Loss, D. Electron spins in quantum dots for spintronics and quantum computation. Solid State Commun. 119, 229–236 (2001).

    CAS  Article  Google Scholar 

  4. 4

    Leuenberger, M. N. & Loss, D. Quantum computing in molecular magnets. Nature 410, 789–793 (2001).

    CAS  Article  Google Scholar 

  5. 5

    Bao, J., Bragas, A. V., Furdyna, J. K. & Merlin, R. Optically induced multispin entanglement in a semiconductor quantum well. Nature Mater. 2, 175–179 (2003).

    CAS  Article  Google Scholar 

  6. 6

    Ardavan, A. & Blundell, S. J. Storing quantum information in chemically engineered nanoscale magnets. J. Mater. Chem. 19, 1754–1760 (2009).

    CAS  Article  Google Scholar 

  7. 7

    DiVincenzo, D. P. The physical implementation of quantum computation. Fortschr. Phys. 48, 771–783 (2000).

    Article  Google Scholar 

  8. 8

    Besombes, L. et al. Probing the spin state of a single magnetic ion in an individual quantum dot. Phys. Rev. Lett. 93, 207403 (2004).

    CAS  Article  Google Scholar 

  9. 9

    Kudelski, A. et al. Optically probing the fine structure of a single Mn atom in an InAs quantum dot. Phys. Rev. Lett. 99, 247209 (2007).

    CAS  Article  Google Scholar 

  10. 10

    Le Gall, C. et al. Optical spin orientation of a single manganese atom in a semiconductor quantum dot using quasiresonant photoexcitation. Phys. Rev. Lett. 102, 127402 (2009).

    CAS  Article  Google Scholar 

  11. 11

    Gupta, J. A., Awschalom, D. D., Peng, X. & Alivisatos, A. P. Spin coherence in semiconductor quantum dots. Phys. Rev. B 59, R10421–R10424 (1999).

    CAS  Article  Google Scholar 

  12. 12

    Liu, W. K. et al. Room-temperature electron spin dynamics in free-standing ZnO quantum dots. Phys. Rev. Lett. 98, 186804 (2007).

    Article  Google Scholar 

  13. 13

    Whitaker, K. M., Ochsenbein, S. T., Polinger, V. Z. & Gamelin, D. R. Electron confinement effects in the EPR spectra of colloidal n-type ZnO quantum dots. J. Phys. Chem. C 112, 14331–14335 (2008).

    CAS  Article  Google Scholar 

  14. 14

    Norberg, N. S. et al. Synthesis of colloidal Mn2+:ZnO quantum dots and high-TC ferromagnetic nanocrystalline thin films. J. Am. Chem. Soc. 126, 9387–9398 (2004).

    CAS  Article  Google Scholar 

  15. 15

    Hausmann, A. & Huppertz, H. Paramagnetic resonance of ZnO:Mn2+ single crystals. J. Phys. Chem. Sol. 29, 1369–1375 (1968).

    CAS  Article  Google Scholar 

  16. 16

    Schweiger, A. & Jeschke, G. Principles of Pulse Electron Paramagnetic Resonance (Oxford Univ. Press, 2001).

    Google Scholar 

  17. 17

    Amin, M. H. S. Rabi oscillations in systems with small anharmonicity. Low Temp. Phys. 32, 198–204 (2006).

    CAS  Article  Google Scholar 

  18. 18

    Fedoruk, G. G. Transient nutation EPR spectroscopy of condensed media. J. Appl. Spectr. 69, 161–182 (2002).

    CAS  Article  Google Scholar 

  19. 19

    Boscaino, R., Gelardi, F. M. & Korb, J. P. Non-Bloch decay of transient nutations in S=1/2 systems: an experimental investigation. Phys. Rev. B 48, 7077–7085 (1993).

    CAS  Article  Google Scholar 

  20. 20

    Salikhov, K. M. & Tsvetkov, Y. D., Electron spin-echo studies of spin–spin interactions in solids, in Time Domain Electron Spin Resonance (eds Kevan, L. & Schwartz, R. N.) 231–277 (Wiley, 1979).

    Google Scholar 

  21. 21

    Tyryshkin, A. M., Lyon, S. A., Astashkin, A. V. & Raitsimring, A. M. Electron spin relaxation times of phosphorous donors in silicon. Phys. Rev. B 68, 193207 (2003).

    Article  Google Scholar 

  22. 22

    Crooker, S. A. et al. Terahertz spin precession and coherent transfer of angular momenta in magnetic quantum wells. Phys. Rev. Lett. 77, 2814–2817 (1996).

    CAS  Article  Google Scholar 

  23. 23

    Dietl, T., Peyla, P., Grieshaber, W. & Merle d'Aubigné, Y. Dynamics of spin organization in diluted magnetic semiconductors. Phys. Rev. Lett. 74, 474–477 (1995).

    CAS  Article  Google Scholar 

  24. 24

    Tribollet, J., Behrends, J. & Lips, K. Ultra long spin coherence time for Fe3+ in ZnO: a new spin qubit. Europhys. Lett. 84, 20009 (2008).

    Article  Google Scholar 

  25. 25

    Mabbs, F. E. & Collison, D. Electron Paramagnetic Resonance of d Transition Metal Compounds Vol. 16 (Elsevier, 1992).

    Google Scholar 

  26. 26

    Witzel, W. M., Hu, X. & Das Sarma, S. Decoherence induced by anisotropic hyperfine interaction in Si spin qubits. Phys. Rev. B 76, 035212 (2007).

    Article  Google Scholar 

  27. 27

    Poitras, C. B. et al. Photoluminescence enhancement of colloidal quantum dots embedded in a monolithic microcavity. Appl. Phys. Lett. 82, 4032–4034 (2003).

    CAS  Article  Google Scholar 

  28. 28

    Le Thomas, N. et al. Cavity QED with semiconductor nanocrystals. Nano Lett. 6, 557–561 (2006).

    CAS  Article  Google Scholar 

  29. 29

    Kahl, M. et al. Colloidal quantum dots in all-dielectric high-Q pillar microcavities. Nano Lett. 7, 2897–2900 (2007).

    CAS  Article  Google Scholar 

  30. 30

    Thomay, T. et al. Colloidal ZnO quantum dots in ultraviolet pillar microcavities. Opt. Express 16, 9791–9794 (2008).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

The authors acknowledge financial support from the US National Science Foundation (CHE 0628252-CRC to D.G.) and the University of Washington. EPR instrumentation support was provided by the Center for Ecogenetics and Environmental Health UW Center grant no. P30 ES07033 from the National Institute of Environmental Health Sciences (NIH). K.M. Whitaker and V.A. Vlaskin are thanked for valuable assistance with the synthesis of the QDs and TEM, respectively.

Author information

Affiliations

Authors

Contributions

S.O. performed the experiments. S.O. and D.G. discussed the results and co-authored the paper.

Corresponding author

Correspondence to Daniel R. Gamelin.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 467 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Ochsenbein, S., Gamelin, D. Quantum oscillations in magnetically doped colloidal nanocrystals. Nature Nanotech 6, 112–115 (2011). https://doi.org/10.1038/nnano.2010.252

Download citation

Further reading