T. Takamasu

Cyclotron resonance in n-type ZnO

Abstract The magnetic field dependence and the temperature dependence of the cyclotron resonance were investigated in n-type ZnO. The observed resonance was assigned as not a conduction electron cyclotron resonance but trapped electron cyclotron resonance from the magnetic field dependence of the resonant energy. The effective mass and the electron–phonon coupling constant were calculated as m * =0.23 m 0 and α =1.2 from the obtained polaron mass, m * pol =0.29 m 0 .

Magnetic-field-induced electronic phase transition in graphite: Pulse field experiment at 3He temperatures

Abstract The magnetic-field-induced electronic phase transition in graphite is investigated over a wide region of the magnetic field-temperature (H-T) plane (H⩽45T and T⩾0.6K) by using a 3He refrigerator and a pulse magnet. A number of new features has been found in the previously unexplored high-field range.

Generation of 500 T fields by electromagnetic flux compression and their application to cyclotron resonance experiments

Abstract Magnetic fields higher than 500 T were generated by means of electromagnetic flux compression. They were applied to cyclotron resonance experiments for bulk GaAs and two-dimensional (2D) elecron systems in GaAs/AlGaAs quantum wells using a CO laser (5.527 μm). A large spin splitting was observed in 2D electron systems even for a carrier concentration higher than n = 10 11 cm −2 . The dependence of the effective mass and the spin splitting on carrier concentration was studied.

Effect of finite electric field on the quantum Hall effect

Abstract Diagonal conductivity σ xx of 2D electrons in GaAs-AlGaAs heterostructures is studied as a function of Hall electric field E y for i =6, 4 and 2 Hall steps, and is compared with calculations taking account of electron heating. The breakdown of the quantum Hall effect is consistently explained for every Hall step in terms of an S-shaped characteristic in the σ xx versus E y relations.

Far-infrared spectroscopy in the spin-Peierls compound CuGeO 3 under high magnetic fields

Polarized far-infrared (FIR) spectroscopic measurements and FIR magneto-optical studies were performed on the inorganic spin-Peierls compound

Observation of resonant hole tunnelling through a (110) oriented AlAs/GaAs/AlAs quantum well

{\mathrm{CuGeO}}_{3}.

Manifestations of quantum chaos in resonant tunnelling

An absorption line, which was found at

Quantum transport phenomena in InAs/GaSb/InAs tunneling devices under high magnetic fields

98 {\mathrm{cm}}^{\ensuremath{-}1}

Investigating the cubic anisotropy of the confined hole subbands of an AlAs/GaAs/AlAs quantum well using resonant magnetotunneling spectroscopy

in the dimerized phase

Transport measurements in short pulsed fields up to 100 T

(D