Long-lived electron spin coherence in CdSe/ZnSSe self-assembled quantum dots

Authors :: Syperek, M.
Yakovlev, D. R.
Yugova, I. A.
Misiewicz, J.
Sedova, I. V.
Sorokin, S. V.
Toropov, A. A.
Ivanov, S. V.
Bayer, M.
Source :: Physical Review B 84, 085304 (2011)
Publication Year :: 2011
Abstract: The electron spin coherence in n-doped and undoped, self-assembled CdSe/Zn(S,Se) quantum dots has been studied by time-resolved pump-probe Kerr rotation. Long-lived spin coherence persisting up to 13 ns after spin orientation has been found in the n-doped quantum dots, outlasting significantly the lifetimes of charge neutral and negatively charged excitons of 350 - 530 ps. The electron spin dephasing time as long as 5.6 ns has been measured in a magnetic field of 0.25 T. Hyperfine interaction of resident electrons with a nuclear spin fluctuations is suggested as the main limiting factor for the dephasing time. The efficiency of this mechanism in II-VI and III-V quantum dots is analyzed.<br />Comment: 9 pages, 7 figures, 1 table