| Project/Area Number |
10044056
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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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 | Research Institute for Scientific Measurements, Tohoku University |
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Principal Investigator |
TANAKA Michiyoshi Res.Inst.For Sci.Meas., Tohoku Univ., Professor, 科学計測研究所, 教授 (90004291)
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| Co-Investigator(Kenkyū-buntansha) |
GOODMAN Peter School of Phys.Univ.of Melbourne, Senior Research Associate, 物理学科, 上級研究員手
SAIYOH Koh Res.Inst.For Sci.Meas., Tohoku Univ., Research Associate, 科学計測研究所, 助手 (50292280)
TSUDA Kenji Res.Inst.For Sci.Meas., Tohoku Univ., Research Associate, 科学計測研究所, 助手 (00241274)
TERAUCHI Masami Res.Inst.For Sci.Meas., Tohoku Univ., Associate Professor, 科学計測研究所, 助教授 (30192652)
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| Project Period (FY) |
1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1998: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Space group determination / Convergent-Beam Electron Doffraction / Coherent Convergent-Beam Electron Diffraction |
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| Research Abstract |
It has been established that convergent-beam electron diffraction (CBED) is quite an effective method for determining crystal point groups and space groups. CBED allows the unique identification of all the 32 point groups and 200 space groups among 230 space groups. However, the other 30 space groups have still remained to be indistinguishable. In the present research, we have newly applied the coherent CBED method to distinguish the remaining space groups. The coherent CBED technique observes interference fringes appearing in the overlapping regions of CBED disks using an high coherency electron source (i.e., field-emission gun), and directly provides phase information of crystal structures. We have applied the method to two pairs of space groups (I23, I2_13) and (I222, I2_12_12_1), which belong to indistinguishable sets because of their same kinematical extinction and no dynamical extinction. We have first discovered that the coherent CBED method can elucidate site symmetries of crystals with respect to the electron prove position. We have successfully proved that coherent CBED can distinguish the space groups of (I23, I2_13) and (I222, I2_12_12_1) through investigating their site symmetries in their unit cells. The present research was carried out in close cooperation with Dr.P.Goodman (University of Melbourne, Australia) and Dr.C.J.Rossouw (CSIRO, Australia).
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