研究目的
To study the structural phase transitions induced by pressure in bulk black phosphorus and to explain the presence of a Raman spectrum above 10 GPa, which should not be observed in an elemental simple cubic system.
研究成果
The study confirmed the presence of Raman components above 10 GPa, which are unexpected in the simple cubic phase. A combined analysis of Raman and XRD data allowed the establishment of presence and extent of coexistence between different structural phases in a wide pressure range (from ~5 up to ~15 GPa). These findings can have an important role in theoretical studies on pressure-induced electronic phase transitions on bulk BP.
研究不足
The study is limited by the pressure ranges achievable with the experimental setups (up to 12.2 GPa for XRD and up to 18.2 GPa for Raman spectroscopy). The non-hydrostatic conditions in Raman experiments may affect the results.
1：Experimental Design and Method Selection:
The study used synchrotron x-ray diffraction for pressures up to
2：2 GPa and Raman spectroscopy up to 2 GPa to investigate the structural phase transitions in bulk black phosphorus. Sample Selection and Data Sources:
A thin BP crystalline platelet was scratched from a polycrystalline sample and loaded in the sample chamber for Raman spectroscopy. For XRD, a small portion of the polycrystalline sample was ground and transferred in silicone oil used as pressure transmitting medium.
3：List of Experimental Equipment and Materials:
A Horiba LabRAM HR Evolution micro-Raman spectrometer, a diamond anvil cell (DAC), a He–Ne laser, NaCl powder as hydrostatic medium, and a ruby chip to determine the working pressure were used for Raman spectroscopy. For XRD, a large x-ray opening screw-driven plate DAC and a
4：5 ? wavelength were used. Experimental Procedures and Operational Workflow:
Raman spectra were collected using a back-scattering geometry. XRD measurements were carried out at the Elettra Synchrotron Trieste.
5：Data Analysis Methods:
Structural refinements of the diffraction data were performed using the General Structure Analysis Software (GSAS).
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