Magnetic Field Dependence of Quadrupolar Splitting and Nuclear Spin Coherence Time in a Strained (110) GaAs Quantum Well

We investigated the magnetic field dependence of quadrupolar splitting and phase relaxation time of nuclear spins in an n-GaAs/AlGaAs (110) quantum well (QW) by optically detected nuclear magnetic resonance (NMR). The NMR spectra show large quadrupolar splitting induced by an internal field gradient...

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Bibliographic Details
Published inJapanese Journal of Applied Physics Vol. 50; no. 4; pp. 04DM03 - 04DM03-3
Main Authors Ishihara, Jun, Ono, Masaaki, Sato, Genki, Matsuzaka, Shunichiro, Ohno, Yuzo, Ohno, Hideo
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.04.2011
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Summary:We investigated the magnetic field dependence of quadrupolar splitting and phase relaxation time of nuclear spins in an n-GaAs/AlGaAs (110) quantum well (QW) by optically detected nuclear magnetic resonance (NMR). The NMR spectra show large quadrupolar splitting induced by an internal field gradient in the QW epilayer. At lower magnetic fields, the quadrupolar splitting become much enhanced, resulting in the appearance of the second order magnetic field dependence of the quadrupole interaction in the NMR spectra. It is also shown that the intrinsic coherence time and the effective coherence time for resonant transitions become shorter as a result that the energy splitting between the two levels becomes small and incoherent transition is occurred by irradiation of an rf magnetic field.
Bibliography:(a) Energy diagram of $I=3/2$ nuclear spin for $\nu_{\text{Q}}=0$ (left) and $\nu_{\text{Q}}\neq 0$ (right). $\nu_{0}$ and $\nu_{\text{Q}}$ are the Zeeman gap and the quadrupolar splitting, respectively. (b) The experimental setup of NMR with rf coil by TRFR measurement. (a) Magnetic field dependence of NMR spectra for 75 As obtained using optically detected NMR at $T=3$ K. At the low magnetic field, the NMR spectrum is asymmetric. (b) Three resonance peaks of the NMR spectrum were plotted for each magnetic field. The central transition can be fitted by $5.4/B_{0}+58.6$ kHz. The FWHM of each resonance peak is plotted as a function of the magnetic field. The intrinsic coherence time $T_{2}$ and the effective coherence time $T_{2}{}^{*}$ of 75 As nuclear spins obtained at $B_{0}=2$ and 0.5 T by pulse NMR for three resonance peaks.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.50.04DM03