Browsing by Author "Adachi, S."

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Anisotropic nature of hole g-factor in individual InAs quantum rings
(2017-02-01)
Kaji, R.
;
Tominaga, T.
;
Wu, Y. -N.
;
Wu, M. -F.
;
Cheng, S. -J.
The in-plane g-factors of electron and hole spins (g perpendicular to e, g perpendicular to h) confined in the individual InAs/GaAs quantum rings (QRs) were investigated by using experimental and theoretical approaches. From the measurements, we found that the experimentally obtained \g perpendicular to h\varies largely from QR to QR, while the variation in \g perpendicular to e\ is small. In addition, the in-plane (x-y) and the out-of-plane (x-z) anisotropies in hole g-factor were obviously confirmed while the electron g-factor exhibits isotropic natures in both cases. From the model calculations, the effects of the shape anisotropies and the uniaxial stress were examined. The shape anisotropy in QRs modifies the spatial distributions of hole wavefunctions. Thus, it brings the resultant changes in the degree of valence-band mixing and \g perpendicular to h\, and combined with uniaxial stress, a larger modulation in \g perpendicular to h\ was achieved. Although more detailed discussions are necessary at this stage, our findings will give valuable information for the g-factor control in semiconductor nanostructures.
Electron and hole in-plane g-factors in single In As quantum rings
(2015-01-01)
Kaji, R.
;
Tominaga, T.
;
Wu, Y. -N.
;
Cheng, S. -J.
;
Adachi, S.
The electron and hole in-plane g-factors were studied in individual InAs/GaAs quantum rings (QRs). From the magneto-photoluminescence measurements under a transverse magnetic field, we evaluated the in-plane g-factors of electron and hole spins by rotating the sample systematically along the crystal growth axis. The experimental results indicate that the in-plane and the out-of-plane anisotropies in hole g-factor are larger than those of electron g-factor, and the value of the hole in-plane g-factor varies largely from QR to QR while the electron g-factor is almost a constant value. From the model calculation considering the effects of shape anisotropies and uniaxial stress, we examined the correlation between the in-plane g-factors and the degree of valence band mixing. Further, the experimentally obtained trend in g-factors was in agreement qualitatively with theoretical consideration.
Hole g-Factor Anisotropies in Individual InAs Quantum Rings
(2016)
Kaji, R.
;
Tominaga, T.
;
Wu, Y. -N.
;
Wu, M. -F.
;
Cheng, S. -J.
We investigated the electron and hole g-factors in individual InAs/GaAs quantum rings (QRs). From the magneto-photoluminescence measurements under a transverse magnetic field, we evaluated the in-plane g-factors of electron and hole spins by rotating the sample systematically around the crystal growth axis. The experimental results indicate that the in-plane and the out-of-plane anisotropies in hole g-factor are larger than those of electron g-factor, and the value of the hole in-plane g-factor varies largely from QR to QR while the electron g-factor is almost a constant value. From the model calculation considering the effects of shape anisotropies and uniaxial stress, we examined the correlation between the in-plane g-factors and the degree of valence band mixing. Further, the experimentally obtained trend in g-factors was in agreement qualitatively with theoretical consideration.