Takao Mizusaki

Spin dynamics of isolated donor electrons in phosphorus-doped silicon from high-frequency electron spin resonance

We present the spin dynamics of isolated donor electrons in phosphorus-doped silicon at low temperature and in a high magnetic field. We performed a steady-state electron spin resonance (ESR) on the sample with a dopant concentration of 6.5 × 10(16) cm(- 3) in a high field of 2.87 T (80 GHz) and at temperatures from 48 down to 1.8 K. As the temperature decreases below 16 K, the resonance spectral line changes from the usual derivative form characteristic of absorptions. Very long spin-lattice relaxation time T(1) at low temperature gives rise to rapid passage effects and results in a dramatic change in the line shape and intensity as a function of temperature. We show that the numerical analysis based on the passage effects well explains the observed spectral changes with temperature. The spin-lattice relaxation time T(1) is derived by numerical fit to the experimental data. We discuss the dynamic nuclear polarization of (31)P nuclear spins which shows up as asymmetric intensities of the hyperfine-split ESR resonance lines.

Phonon echoes in Si:P at very low temperature

We observed phonon echoes in P-doped Si (Si:P) at very low temperatures. We applied two radio-frequency pulses separated by a time delay of ? on Si:P and observed echo signal at t = 2? in both insulating and metallic samples with varying dopant concentrations and of different sample forms of powders and bulk plates at temperature between 45 mK and 4 K. The echoes were much more pronounced in insulating powder samples than in metallic ones and in bulk ones. The echo intensity for a fixed ? increased very strongly as temperature was lowered but the echoes disappeared toward the superfluid-to-normal transition temperature of helium mixture in which the samples were immersed. We observed no appreciable change in the echo intensities as external magnetic field was varied up to 8 T. The echoes are interpreted to be dynamical polarization phonon echoes in piezoelectric powders of insulating Si:P with a dopant concentration n = 6 x 1017 cm-3.

High field ESR of P-doped Si for Quantum Computing Application

We measured ESR of phosphorous-doped silicon with a low concentration of P, n, at high magnetic fields and low temperatures to investigate the states of nuclear spin. A sample with n = 6.52 × 1016 /cm3 was studied at 2.85 T (80 GHz) from 30 K to 2.3 K by field-modulating cw-ESR for a fixed 0 dB power. As the temperature was lowered, the out-of-phase signal appeared around 18 K, reached at a maximum intensity at 13 K, and disappeared around 6 K. The out-of-phase signal is referred to the field modulation. The in-phase signal started to change from the derivative of absorption spectrum at high temperatures to absorption-like shape around 15 K and asymmetry of intensity for two peaks of hyperfine-separated signals increased as temperatures was lowered. Below 10 K, the saturation of the in-phase signal started to appear. We speculate that the asymmetry is caused by saturation effect and dynamic nuclear polarization of 31P nuclear spin due to drastic change of electron T1.

Microscopic control of Si-29 nuclear spins near phosphorus donors in silicon

We demonstrate an efficient control of

Kick-up frame connection structure

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Spin Coherence Time T2 in Metallic P-doped Si at Very Low Temperature

Si nuclear spin orientation for specific lattice sites near

Rechargeable battery mounting structure

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Dynamic Nuclear Polarization of Phosphorus in Silicon in Strong Magnetic Fields and Low Temperatures

P donors in silicon crystals at temperatures below 1 K and in high magnetic field of 4.6 T. Excitation of the forbidden electron-nuclear transitions leads to a pattern of narrow holes and peaks in the ESR lines of

希薄ドープSi:Pの31p核スピン状態観測のためのESR/NMR 二重共鳴システムの開発とESRによる動的核偏極効果の測定

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Structure for supporting suspension devices for vehicle

P. The pattern originates from dynamic polarization the