Temperature dependence of electron-spin
coherence in intrinsic bulk GaAs
1
Tianshu Lai
*
, Xiaodong Liu, Haihong Xu, Zhongxing Jiao, Jinhui Wen and Weizhu Lin
State-Key Laboratory of Optoelectronic Materials and Technologies, Department of Physics
Zhongshan (Sun Yat-Sen) University, Guangzhou, Guangdong 510275, P. R. China
stslts@mail.sysu.edu.cn
Abstract
Temperature dependence of electron-spin coherence dynamics is investigated for an
intrinsic bulk GaAs in the Voigt geometry using the elliptically polarized absorption
quantum beat spectroscopy. Temperature dependences of spin coherence and
recombination lifetimes as well as g factor of electrons are reported over a
temperature range from 8.1 to 260 K. The temperature dependence of spin coherence
lifetime (
) agrees well with a reported theoretical calculation and can be fit well by
a relationship
, which provides an evidence to support electron-spin
decoherence dominated by BAP mechanism. The temperature dependence of g factor
also agrees well with results reported.
*
2
T
2/1*
2
~
−
TT
Keywords: Spin coherence, temperature dependence, elliptically polarized
absorption quantum beats, GaAs.
1 Introduction
The realization of spintronic devices necessitates the ability to preserve spin information over a
practical device length and time scale. Therefore, explorations of the relaxation and transport of
electron spins become an emerging interest in semiconductors and quantum structures. Some of
exciting research results has been reported for GaAs/AlGaAs quantum wells [1-3] and n-GaAs [4-6]. A
spin coherence lifetime of a few nanoseconds and a spatial transport scale over 100 µm have been found
in the n-doped GaAs [4-6]. Spin coherence transfer has also been observed between CdSe quantum dots
bridged by conjugated molecules [7]. These results have additionally raised the possibility that spin
coherence may eventually enable quantum computation in solid-state systems. However, in contrast to
n-GaAs and GaAs quantum wells, the spin coherence dynamics of the intrinsic bulk GaAs is understood
poorly. Sparse reports concern it [8]. Even a temperature dependence of spin coherence lifetime is
unavailable so far. As a consequence, the temperature dependence of spin coherence lifetime of a
n-GaAs had to be cited as a contrast in the temperature-dependent calculation of spin lifetime of an
intrinsic GaAs so that a large difference was resulted in [9].
In this letter, a temperature-dependent electron-spin coherence dynamics in an intrinsic GaAs has be
investigated experimentally by means of the elliptically polarized absorption quantum beat
spectroscopy (EPAQBS) [10]. A temperature-dependent spin coherence lifetime has been given. In
1
Projects supported by NSF of China (grant No. 60490295) and Specialized Research Fund for the Doctoral
Program of Higher Education (grant No. 20050558030)
http://www.paper.edu.cn
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