TY - JOUR
T1 - 1/f 2 spectra of decoherence noise on 75As nuclear spins in bulk GaAs
AU - Sasaki, Susumu
AU - Miura, Takanori
AU - Ikeda, Kosuke
AU - Sakai, Masahiro
AU - Sekikawa, Takuya
AU - Saito, Masaki
AU - Yuge, Tatsuro
AU - Hirayama, Yoshiro
N1 - Funding Information:
The authors acknowledge financial supports from Tohoku University CSRN and KAKENHI Grants (Nos. 26287059 and 15H05867). S.S. and Y.H. are grateful to stimulated discussions in the meetings of Cooperative Research Project of Research Institute of Electrical Communication, Tohoku University. S.S. is also supported partly by the joint research program of Research Institute of Electrical Communication (RIEC) Tohoku University, the collaboration program of Institute of Materials and Systems for Sustainability (IMaSS), Nagoya University, KAKENHI grants (No 19H02580), the Naito Scholarship Foundation and the Yamgaguchi Educational and Scholarship Foundation.
Publisher Copyright:
© 2020, The Author(s).
PY - 2020/12/1
Y1 - 2020/12/1
N2 - To identify the decoherence origin, frequency spectra using multiple π-pulses have been extensively studied. However, little has been discussed on how to define the spectral intensities from multiple-echo decays and how to incorporate the Hahn-echo T2 in the noise spectra. Here, we show that experiments based on two theories solve these issues. As proved in the previous theory, the spectral intensity is given as the decay in the long-time limit. Unlike the initial process of decays, this definition is not only theoretically proven but also validated experimentally, since long-time behaviors are generally free from experimental artifacts. The other is the fluctuation–dissipation theory, with which the Hahn-echo T2 is utilized as the zero-frequency limit of the noise spectrum and as an answer to the divergent issue on the 1/fn noises. As a result, arsenic nuclear spins are found to exhibit 1/f2 dependences over two orders of magnitude in all the substrates of un-doped, Cr-doped semi-insulating and Si-doped metallic GaAs at 297 K. The 1/f2 dependence indicates that the noise is dominated by a single source with characteristic frequency fcun = 170 ± 10 Hz, fcCr = 210 ± 10 Hz and fcSi = 460 ± 30 Hz. These fc values are explained by a model that the decoherence is caused by the fluctuations of next-nearest-neighboring nuclear spins.
AB - To identify the decoherence origin, frequency spectra using multiple π-pulses have been extensively studied. However, little has been discussed on how to define the spectral intensities from multiple-echo decays and how to incorporate the Hahn-echo T2 in the noise spectra. Here, we show that experiments based on two theories solve these issues. As proved in the previous theory, the spectral intensity is given as the decay in the long-time limit. Unlike the initial process of decays, this definition is not only theoretically proven but also validated experimentally, since long-time behaviors are generally free from experimental artifacts. The other is the fluctuation–dissipation theory, with which the Hahn-echo T2 is utilized as the zero-frequency limit of the noise spectrum and as an answer to the divergent issue on the 1/fn noises. As a result, arsenic nuclear spins are found to exhibit 1/f2 dependences over two orders of magnitude in all the substrates of un-doped, Cr-doped semi-insulating and Si-doped metallic GaAs at 297 K. The 1/f2 dependence indicates that the noise is dominated by a single source with characteristic frequency fcun = 170 ± 10 Hz, fcCr = 210 ± 10 Hz and fcSi = 460 ± 30 Hz. These fc values are explained by a model that the decoherence is caused by the fluctuations of next-nearest-neighboring nuclear spins.
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U2 - 10.1038/s41598-020-67636-9
DO - 10.1038/s41598-020-67636-9
M3 - Article
C2 - 32606323
AN - SCOPUS:85087112662
SN - 2045-2322
VL - 10
JO - Scientific Reports
JF - Scientific Reports
IS - 1
M1 - 10674
ER -