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利用时间分辨法拉第旋转光谱技术研究了室温下CdSe胶体量子点的自旋相干特性. 获得了不同磁场下的自旋退相干时间,并分析了自旋退相干的物理机理. 零磁场时量子点激子自旋退相干时间为102 ps,主要受电子与核自旋之间的超精细相互作用所影响. 当外加横向磁场强度为250 mT时,激子自旋退相干时间为294 ps;增大磁场强度, 自旋退相干时间逐渐减小.在较强磁场环境中(≥250 mT), 量子点激子自旋动力学由非均匀退相干机制所主导.
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关键词:
- 自旋相干 /
- 量子点 /
- CdSe /
- 时间分辨法拉第旋转光谱
Time-resolved Faraday rotation spectroscopy is used to study the spin coherence in colloidal CdSe quantum dots at room temperature. Spin dephasing time and relevant dephasing mechanisms are analyzed in different transverse magnetic fields. The exciton spin-dephasing time is 102 ps in a zero magnetic field, which is affected by hyperfine interaction between electron and nuclear spins. In a transverse magnetic field of 250 mT, the exciton spin-dephasing time becomes 294 ps due to the fact that the presence of magnetic field makes the nuclear spin fluctuations unimportant. Further increasing the external magnetic field, the spin dephasing time becomes shorter. The magnetic field dependence of the exciton spin dynamics shows that the spin dynamics is dominated by the inhomogeneous dephasing in high magnetic fields (≥ 250 mT).-
Keywords:
- spin coherence /
- quantum dots /
- CdSe /
- time-resolved Faraday rotation spectroscopy
[1] Henneberger F, Benson O 2008 Semiconductor Quantum Bits (Singapore: World Scientific)
[2] Dyakonov M I 2008 Spin Physics in Semiconductors (Berlin: Springer-Verlag)
[3] Jiang H L, Zhang R J, Zhou H M, Yao D Z, Xiong G G 2011 Acta Phys. Sin. 60 017204 (in Chinese) [蒋洪良, 张荣军, 周宏明, 姚端正, 熊贵光 2011 60 017204]
[4] Meyer F, Zakharachenya B P 1984 Optical Orientation (Amsterdam: North-holland)
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[8] Syperek M, Yakovlev D R, Yugova I A, Misiewicz J, Sedova I V, Sorokin S V, Toropov A A, Ivanov S V, Bayer M 2011 Phys. Rev. B 84 085304
[9] Akimov I A, Feng D H, Henneberger F 2006 Phys. Rev. Lett. 97 056602
[10] Feng D H, Akimov I A, Henneberger F 2007 Phys. Rev. Lett. 99 036604
[11] Gupta J A, Awschalom D D, Efros Al L, Rodina A V 2002 Phys. Rev. B 66 125307
[12] Crooker S A, Awschalom D D, Baumberg J J, Flack F, Samarth N 1997 Phys. Rev. B 56 7574
[13] Liu W K, Whitaker K M, Smith A L, Kittilstved K R, Robinson B H, Gamelin D R 2007 Phys. Rev. Lett. 98 186804
[14] Leatherdale C A, Woo W K, Mikulec F V, Bawendi M G 2002 J. Phys. Chem. B 106 7619
[15] Dou X M, Sun B Q, Jiang D S, Ni H Q, Niu Z C 2012 J. Appl. Phys. 111 053524
[16] Jiang J H, Wang Y Y, Wu M W 2008 Phys. Rev. B 77 035323
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[1] Henneberger F, Benson O 2008 Semiconductor Quantum Bits (Singapore: World Scientific)
[2] Dyakonov M I 2008 Spin Physics in Semiconductors (Berlin: Springer-Verlag)
[3] Jiang H L, Zhang R J, Zhou H M, Yao D Z, Xiong G G 2011 Acta Phys. Sin. 60 017204 (in Chinese) [蒋洪良, 张荣军, 周宏明, 姚端正, 熊贵光 2011 60 017204]
[4] Meyer F, Zakharachenya B P 1984 Optical Orientation (Amsterdam: North-holland)
[5] Merkulov I A, Efros Al L, Rosen M 2002 Phys. Rev. B 65 205309
[6] Khaetskii A V, Loss D, Glazman L 2002 Phys. Rev. Lett. 88 186802
[7] Gupta J A, Awschalom D D, Peng X, Alivisatos A P 1999 Phys. Rev. B 59 R10421
[8] Syperek M, Yakovlev D R, Yugova I A, Misiewicz J, Sedova I V, Sorokin S V, Toropov A A, Ivanov S V, Bayer M 2011 Phys. Rev. B 84 085304
[9] Akimov I A, Feng D H, Henneberger F 2006 Phys. Rev. Lett. 97 056602
[10] Feng D H, Akimov I A, Henneberger F 2007 Phys. Rev. Lett. 99 036604
[11] Gupta J A, Awschalom D D, Efros Al L, Rodina A V 2002 Phys. Rev. B 66 125307
[12] Crooker S A, Awschalom D D, Baumberg J J, Flack F, Samarth N 1997 Phys. Rev. B 56 7574
[13] Liu W K, Whitaker K M, Smith A L, Kittilstved K R, Robinson B H, Gamelin D R 2007 Phys. Rev. Lett. 98 186804
[14] Leatherdale C A, Woo W K, Mikulec F V, Bawendi M G 2002 J. Phys. Chem. B 106 7619
[15] Dou X M, Sun B Q, Jiang D S, Ni H Q, Niu Z C 2012 J. Appl. Phys. 111 053524
[16] Jiang J H, Wang Y Y, Wu M W 2008 Phys. Rev. B 77 035323
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