2001 Fiscal Year Final Research Report Summary
New Type of Nonlinear Optical Device using Charge-Density-Wave Collective Motion
| Project/Area Number |
12650039
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | Japan Advanced institute of Science and Technology |
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Principal Investigator |
KOYANO Mikio Japan Advanced Institute of Science and Technology, School of Materials Science, Associate Professor, 材料科学研究科, 助教授 (60195873)
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| Co-Investigator(Kenkyū-buntansha) |
KATAYAMA Shin'ichi Japan Advanced Institute of Science and Technology, School of Materials Science, Professor, 材料科学研究科, 教授 (30018270)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Transition-metal dichalcogenide / Charge-density-wave / Nonlinear conduction / Quasi-particle / Screening effect / Two-dimensional electron gas |
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| Research Abstract |
(i) Charge density fluctuation and density modulation in ideal 2-dimensional electron systems
Resonant light scattering spectra from modulation doped n-type AlGaAs/GaAs single heterojunctions are studied experimentally and theoretically. Based on the light scattering formula due to the charge-density mechanism, the scattering intensities by coupled intersubband plasmon-LO phonon modes are analyzed by taking into account the electron-electron and electron-phonon interactions. Moreover, we carry out a self-consistent calculation of the density modulation of the 2-dimensional electron gas in a lateral surface superlattice.
(ii) Charge-density-waves in transition-metal dichalcogenides
Single crystals of quasi-two-dimensional conductor of TaS_2 have been synthesized by chemical vapor transport technique. Excess sulfur addition at the synthesis suppressed the charge-density-wave transition through a conduction carrier injection; the thermopower measurements revealed that the injected carrier is hole.
(iii) Photo-irradiation effect on dynamics of charge-density-wave condensate in quasi-one-dimensional conductors
We find a new photo-irradiation effect on the current-voltage characteristics of quasi-one-dimensional conductors TaS_3. When the TaS_3 single crystal is irradiated with a weak 488 nm emission from Ar^+ laser, the electrical current is enhanced around the threshold voltage V_t below the Peierls transition temperature T_p. The current enhancement is attributed to the increase of charge-density-wave contribution due to the screened pinning potentials by photo-excited quasi-particles in plastic creep phase of charge-density-wave motion.
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