Fig. 1. (a) Optical image of SCG, with the upper left insert showing an SEM image of SCG after laser cutting. (b) Raman spectrum of laser-cut SCG with a 532 nm excitation laser under ambient conditions.

Fig. 2. (a) Optical photographs of SCG surface morphology under different pressures in Ar. (b) and (c) 2D Frequency_G distribution imaging maps and 2D FWHM_G distribution imaging maps of SCG under different pressures in Ar, respectively. Images were acquired at 1.5, 6.5, 18.0, 19.3, 21.3, and 28.3 GPa.

Fig. 3. (a) and (b) Distribution diagrams of Frequency_G and FWHM_G, respectively, under different pressures in Ar. The solid line represents the Gaussian fit to the statistical distribution. (c) Raman spectra of folding area (red solid lines) and planar area (blue solid lines) of SCG under different pressures. The upper right insert is an optical image of SCG at 19.3 GPa, and the red and blue dashed boxes are enlarged images of the Raman spectrum acquisition positions of the folding and planar areas, respectively.

Fig. 4. (a) Optical photographs of SCG surface morphology acquired at 2.1, 11.0, 18.8, and 25.8 GPa in He. (b) Optical photographs of changes in SCG morphology with time at the pressure of 18.8 GPa, taken at 1 s, 3 s, 6 min, 17 min, and 10 h. (d) Optical photographs of SCG surface morphology acquired at 4., 12.0, 16.1, and 20.5 GPa in cBN. (d) Optical photographs of changes in SCG morphology with time at the pressure of 16.1 GPa, taken at 1 s, 5 min, 17 min, 27 min, and 10 h.

Fig. 5. (a) and (b) 2D Frequency_G and 2D FWHM_G distribution imaging maps of SCG surface acquired at 2.1, 11.0, 18.8, and 25.8 GPa in He. (c) and (d) Statistical diagrams of Frequency_G and FWHM_G distributions, respectively, under different pressures in He.

Fig. 6. (a) and (b) 2D Frequency_G and 2D FWHM_G distribution imaging maps of SCG surface acquired at 4.2, 12.0, 16.1, and 20.5 GPa in cBN. (c) and (d) Statistical diagrams of Frequency_G and FWHM_G distributions, respectively, under different pressures in cBN.

Fig. 7. (a)–(c) SEM images of pristine SCG, SCG recovered from Ar (28.3 GPa), and SCG recovered from He (25.8 GPa), respectively. The yellow dotted boxes and arrows show the AFM scanning areas and directions. (d)–(f) 2D AFM images corresponding to the positions indicated by the yellow dotted boxes in (a)–(c), respectively. The bottom left inserts how the size distributions of striped segmented regions. (g)–(i) 3D AFM images corresponding to the positions indicated by the yellow dotted boxes in (a)–(c), respectively.