| Project/Area Number |
14540299
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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 |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
HAYASHI Tetsusuke Kyoto University, Graduate School of Human and Environmental Studies, Professor, 大学院・人間・環境学研究科・高等教育研究開発推進センター, 教授 (80026799)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAI Masanobu Kyoto University, Department of Physics, Research Associate, 大学院・理学研究科, 助手 (30303803)
WATANABE Masayuki Kyoto University, Graduate School of Human and Environmental Studies, Research Associate, 大学院・人間・環境学研究科, 助手 (20240525)
TANAKA Koichiro Kyoto University, Department of Physics, Professor, 大学院・理学研究科, 教授 (90212034)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2002: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | PHASE TRANSITION / ELECTRONIC EXCITATION / LATTICE RELAXATION / PHOTOLUMINESCENCE / インコメンシュレート相転移 / 励起子 / 光音響効果 |
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| Research Abstract |
The purpose of this research project is to clarify the relation between the dynamical relaxation processes of electronic excited states and the structural phase transitions in ionic crystals.
(1)Structure of charge-separated self-tapped states of excitons in lead halides
Optically stimulated EPR investigations have been made on PbBr_2 and PbCl_2 crystals. Excitons in these crystals undergo charge separated relaxation into self-trapped electrons and holes due to the strong interaction with phonons. The structures of these self-trapped states were determined with EPR analysis; electrons are localized on Pb ion pairs and holes on halogen molecules (PbBr_2) and on isolated Pb atoms (PbCl_2), giving the primary process of photochemical changes.
(2)Relaxation_of electronic excitation under phase transitions in Cs_2CdI_4:Mn and Rb_2CdI_4:Mn
Photoluminescence spectra and the decay times of Mn ion centers were investigated in a wide temperature range across the phase transition temperatures in these crystals. The strong lattice relaxation was found to occur in the intermediate phase, the so-called incommensurate phase in Cs_2CdI_4. A similar behavior of photoluminescence revealed the existence of phase transitions in Rb_2CdI_4 which have not been reported so far.
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