T. Tokumoto

Area of research

Electronic, Optical and Magnetic Materials · Condensed Matter Physics

Research interest

Research topics from publications: Electronic structure and magnetic symmetry in MnTiO3analyzed by second harmonic generation; Cyclotron decay time of a two-dimensional electron gas from 0.4 to 100 K; Ba2TeO: A new layered oxytelluride; Temperature- and field-dependent energy transfer in CdSe nanocrystal aggregates studied by magneto-photoluminescence spectroscopy; Ultrafast pump–probe spectroscopy in gallium arsenide at 25 T; Short-range magnetic interactions and optical band-edge physics inSrCu2(BO3)2</mml:; Ultrafast Pump-probe Spectroscopy in Gallium Arsenide at 25 Tesla; Decoherence in a Landau Quantized Two Dimensional Electron Gas. Representative work: Second harmonic generation (SHG) and linear absorbance spectra of MnTiO${}_{3}$ were measured and the 1.88, 2.41, 2.63, and 3.06 eV SHG features were identified as $d\ensuremath{-}d$ optical transitions from ${}^{6}{A}_{1g}$ to ${}^{4}{T}_{1g}{(}^{4}G)$, ${}^{4}{T}_{2g}{(}^{4}G)$, ${{}^{4}{E}_{g}$,${}^{4}{A}_{1g}{(}^{4}G)}$, and ${}^{4}{E}_{g}{(}^{4}D)$, respectively. These zero-phonon transitions were used to calculate the octahedral crystal field splitting energy (${\ensuremath{\Delta}}_{0}$) and the Racah parameters $B$ and $C$. The SHG spectra showed significant distinctions between the antiferromagnetic and the paramagnetic or spin-flop phases. The polarization dependence of the SHG in We have studied the cyclotron decay time of a Landau-quantized two-dimensional electron gas as a function of temperature (0.4--100 K) at a fixed magnetic field ($\ifmmode\pm\else\textpm\fi{}1.25\phantom{\rule{0.16em}{0ex}}\mathrm{T}$) using terahertz time-domain spectroscopy in a gallium arsenide quantum well with a mobility of ${\ensuremath{\mu}}_{dc}=3.6\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{V}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$ and a carrier concentration of ${n}_{s}=2\ifmmode\times\else\texttimes\fi{}{10}^{11}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremat