1991 Fiscal Year Final Research Report Summary
Molecular Level Lattice Dynamics of Molecular Assembly Film
| Project/Area Number |
01420008
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
ISHIGURO Takehiko Kyoto University, Physics, Professor, 理学部, 教授 (50202982)
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| Co-Investigator(Kenkyū-buntansha) |
SUGI Michio Electrotechnical Lab., Head Researcher, 首席研究官
MOGAMI Yoshio Kyoto University, Physics, Instructor, 理学部, 助手 (10202251)
FUKUDOME Hideo Kyoto University, Physics, Professor, 理学部, 教授 (90025289)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Molecular Assembly Film / Langmuir-Blodgett Film / Hetero-LB Film / Phonon Spectroscopy / Phonon Stop Band / Superconducting Tunneling Junction / Guinier Effect / Lattice Dynamics |
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| Research Abstract |
In this research project we intended to explore the method of phononspectroscopy to clarify the lattice dynamics of molecules forming molecular assembly films such as Langmuir-Blodgett films. Those molecules consist of long alkyl chains and heavy metal ions, which are bounded weakly. The phonons emitted from a superconducting tunnel junction cover wavenumbers corresponding to fundamental resonance of the molecules. We have developed the experimental methods of the phononspectroscopy and the fabrication technique of high quality of the LB multilayer films. For the heterostructured LB film, we discovered anomalous diffraction vector shifts for multilayer with dimerized configuration with respect to metal ions such as Cd. We carried out elaborate studies to confirm the observation and to clarify the detailed structure, experimentally and analytically. As a result we conclude that this is ascribed to the size effect appearing in conventional alloys after Guinier. For the LB films with predetermined one-dimensional stacking, the effect appeared dramatically. To apply the superconducting tunnel junction spectroscopy, it is essential to construct thin film devices on the LB film by evaporation from the phonon stop band specific to the LB multilayer for the first time. This has two important implications. First we proved that the device needing the control of nm thickness can be constructed on the LB multilayer. This should be strong encouragement for technological development such as molecular assembly devices. Secondly the phononspectroscopy can be useful means to investigate the lattice dynamics by deducing the phonon stop band, which cannot be covered by any other means. The lattice dynamics of molecules is very interesting due to their specific structure, but it is too complicated to approach by model calculation. They definitely need experimental approach like present case to lead investigation.
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