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Guest-Host Interaction and High-pressure Phase Transitions in Semiconductor Clathrates Studied by Raman Spectromopy

Research Project

Project/Area Number 18540315
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Condensed matter physics I
Research InstitutionGifu University

Principal Investigator

SHIMIZU Hiroyasu  Gifu University, Faculty of Engineering, Prof (80023258)

Co-Investigator(Kenkyū-buntansha) SASAKI Shigeo  Gifu University, Faculty of Engineering, Assoc. Prof (30196159)
KUME Tetsuji  Gifu University, Faculty of Engineering, Assis.Prof (30293541)
Project Period (FY) 2006 – 2007
Project Status Completed (Fiscal Year 2007)
Budget Amount *help
¥3,800,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥300,000)
Fiscal Year 2007: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2006: ¥2,500,000 (Direct Cost: ¥2,500,000)
KeywordsRaman Scattering / Semiconductor Clathrate / Nano-Structure / Rattling Vibration / High Pressure / Guest-Host Interaction
Research Abstract

1.High-pressure Raman and XRD measurements of a defect clathrate Ba_8Ge_(43) □_3 have been carried out at room temperature up to 40 GPa. Raman spectra show a pressure-induced phase transition at 8 GPa, which is due to the structural distortion through the three-bonded Ge atoms and to the change in the guest-host electronic interaction.
Both Raman spectra and XRD patterns present the evidence for the amorphization of Ba_8Ge_(43) around 30-40 GPa. The isostructural phase transition associated with the large volume reduction was not observed for Ba_8Ge_(43) up to 40 GPa. The pressure dependence of the lattice constant (a) normalized by a_0 at 1 bar ( ; a/s_0) shows the continuous decrease with pressure until amorphization. From the good coincidence of these curves between Ba_8Ge_(43) and Ba_sSi_(46) at pressures above 15 GPa, we propose that the isostructural phase transition found for Ba_8Si_(46) at 15 GPa may be originated from a defect-induced transformation to Ba_sSi_(43) □_3 with the … More help of their theoretical EOS by the first-principles calculations.
2.High-pressure Raman measurements of type-III germanium clathrate Ba_(24)Ge_(100) has been made up to 26 GPa at room temperature. We observed low-frequency vibrational (rattling) modes associated with guest Ba atoms at 25-50 cm^(-1), and host Ge framework vibrations around 50-250 cm^(-1), which are compared with those of silicon clathrate Ba_(24)Si_(100). High-pressure phase transition was found at 3.2 GPa, which seems to be due to the structural distortion combined with the enhanced guest-host interactions.
Ba_(24) Ge_(100) becomes irreversibly amorphous at pressures above 22 GPa. This pressure is less than that of type-I Ba_8Ge_(43) clathrate, indicating that type-III structure is less stable than type-I Ge clathrate under high pressures.
The present results throw valuable light on the understanding and the application of semiconductor clathrates, the high pressure phase tuansitions, and the general system of guest-host interactions. Less

Report

(3 results)
  • 2007 Annual Research Report   Final Research Report Summary
  • 2006 Annual Research Report
  • Research Products

    (15 results)

All 2008 2007

All Journal Article (12 results) (of which Peer Reviewed: 5 results) Presentation (3 results)

  • [Journal Article] High-pressure Raman study of nano-channel materials: BaAl_2Si_2 and BaSi_62008

    • Author(s)
      Y. Narita, et. al.
    • Journal Title

      J. Phys. Conf. Series (印刷中)

    • Related Report
      2007 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Raman and x-ray diffraction studies of Ba doped germanium clathrate Ba_8Ge_<43> at high pressures2007

    • Author(s)
      H. Shimizu, et. al.
    • Journal Title

      J. Appl. Phys. 101

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] High-pressure Raman study on two modifications of BaAl_2Si_22007

    • Author(s)
      H. Shimizu, et. al.
    • Journal Title

      Phys. stat. solidi(b) 244

      Pages: 357-361

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] High-pressure Raman study of Ba doped type-III germanium clathrate Ba_<24>Ge_<100> up to 26 GPa2007

    • Author(s)
      H. Shimizu, et. al.
    • Journal Title

      J. Appl. Phys. 101

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] Raman and x-ray diffraction studies of ba doped germanium clathrate Ba_*Ge_<43> at high pressures2007

    • Author(s)
      H. Shimizu, T. Iitaka, T. Fukushima, T. Kume, S. Sasaki, et. al.
    • Journal Title

      Journal of Applied Physics 101

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Journal Article] High-pressure Raman study on two modifications of BaAl_2Si_22007

    • Author(s)
      H. Shimizu, T. Kume, Y. Narita, S. Sasaki, et. al.
    • Journal Title

      physica status solidi b 244

      Pages: 357-361

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Journal Article] High-pressure Raman study of Ba doped type-III germanium clathrate Ba_<24>Ge_<100> up to 26 GPa2007

    • Author(s)
      H. Shimizu, T. Fukushima, T. Kume, S. Sasaki, et. al.
    • Journal Title

      Journal of Applied Physics 101

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Journal Article] High-pressure Raman study of Ba doped type-III germanium clathrate Ba_<24>Ge_<100>up to 26 GPa2007

    • Author(s)
      H. Shimizu, et. al.
    • Journal Title

      J. Appl. Phys. 101

    • Related Report
      2007 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Raman and x-ray diffraction studies of Ba doped germanium clathrate Ba_8 Ge_<43> at high pressures2007

    • Author(s)
      H.Shimizu et al.
    • Journal Title

      J. Appl. Phys. 101・6

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Raman study of semiconductor clathrates under high pressure2007

    • Author(s)
      T.Kume et al.
    • Journal Title

      Phys. stat. solidi(b) 244・1

      Pages: 352-356

    • Related Report
      2006 Annual Research Report
  • [Journal Article] High-pressure Raman study on two modifications of BaAl_2Si_22007

    • Author(s)
      H.Shimizu et al.
    • Journal Title

      Phys. stat. solidi(b) 244・1

      Pages: 357-361

    • Related Report
      2006 Annual Research Report
  • [Journal Article] High-pressure Raman study on type I germanium clathrate2007

    • Author(s)
      T.Fukushima et al.
    • Journal Title

      Phys. stat. solidi(b) 244・1

      Pages: 392-396

    • Related Report
      2006 Annual Research Report
  • [Presentation] 構造I型Ga-Ge混晶クラスレートの高圧X線回折およびラマン散乱2008

    • Author(s)
      清水 宏晏
    • Organizer
      日本物理学会
    • Place of Presentation
      近畿大学
    • Year and Date
      2008-03-24
    • Related Report
      2007 Annual Research Report
  • [Presentation] Semiconductor Clathrates at High Pressure2007

    • Author(s)
      H. Shimizu and T. Kume
    • Organizer
      Workshop on Advances in High Pressure Crystallography
    • Place of Presentation
      The University of Oxford
    • Year and Date
      2007-09-05
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Semiconductor Clathrates at High Pressure2007

    • Author(s)
      H. Shimizu, T. Kume
    • Organizer
      Workshop on Advances in High Pressure Crystallography at Large Scale Facilities
    • Place of Presentation
      Univ. of Oxford
    • Year and Date
      2007-09-05
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary

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Published: 2006-04-01   Modified: 2020-05-15  

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