Raman spectrum and lattice parameters of MgB2 as a function pressure

Authors:
  • AGAlexander F. Goncharov
    Alexander F. Goncharov
  • VSViktor V. Struzhkin
    Viktor V. Struzhkin
  • EGEugene Gregoryanz
    Eugene Gregoryanz
  • JHJingzhu Hu
    Jingzhu Hu
  • RHRussell J. Hemley
    Russell J. Hemley
  • HMHo-Kwang Mao
    Ho-Kwang Mao
  • GLG. Lapertot
    G. Lapertot
  • SBS. L. Bud'Ko
    S. L. Bud'Ko
  • PCP. C. Canfield
    P. C. Canfield
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Abstract
We report Raman spectra and synchrotron x-ray diffraction measurements of lattice parameters of polycrystalline MgB2 under hydrostatic pressure conditions up to 15 GPa. An anomalously broadened Raman band at 620 cm-1 is observed that exhibits a large linear pressure shift of its frequency. The large mode damping and Gruneisen parameter indicate a highly anharmonic nature of the mode, broadly consistent with theoretical predictions for the E2g in-plane boron stretching mode. The results obtained may provide additional constraints on the electron-phonon coupling in the system.