Fig. 3
In situ high-pressure XRD of amorphous diamond. a XRD patterns of the amorphous diamond sample as a function of pressure. The X-ray wavelength is 0.4066 Å. Diffraction peaks from the pressure medium helium are marked by symbol *. b Pressure vs. fractional volume changes for glassy carbon (circles)25, crystalline diamond (black solid line) and amorphous diamond (squares for experimental results, red solid line for simulation results). The dashed line is a second-order BM-EOS fit to the experimental data. The volume change of amorphous materials is estimated by assuming a cubic power law between the volume and the inverse position of the diffraction peak (q−1). The peak position was derived by fitting the diffraction peaks to a Gaussian function. c Bulk moduli and atomic number densities of amorphous diamond, a-Si10, a-Ge, SiO2 glass, GeO2 glass35, amorphous BOx 32, and amorphous alloys (metallic glasses)34. The error bars of pressures were estimated by measuring pressure before and after each XRD measurement
