Graphite under pressure: Equation of state and first-order Raman modes

Nanoscale pressure effects in individual double-wall carbon nanotubes

“…5 The mean internal radius is 0.7 nm and the mean external radius is 1.04 nm for the sample used here. Using the elastic constants of graphite 12,29 and considering the elastic continuum model for DWCNTs we find a pressure coefficient for the internal ͑ex-ternal͒ tube of −0.8p͑−1.7p͒, which corresponds to 3.8 cm −1 / GPa ͑8.1 cm −1 / GPa͒. The pressure coefficients we observe for argon are close to these values and are within the same order of magnitude for the pressure media considered here.…”

“…X-ray diffraction studies of graphite at 10 GPa show that the lattice in-plane deformation is 1% with a lattice out of plane deformation of 12%. 29 This indicates that the lateral stress due to anisotropic interaction of the molecules of the pressure medium with the tube wall does not play an important role here. The density of the medium around the tube has already been investigated: Bienfait et al 33 conclude from molecular dynamics simulations that argon adsorbs epitaxially on the hexagonal lattice of the tube walls.…”

Shock-compressed graphite to diamond transformation on nanosecond time scales

“…For the graphite phase, parameters for Eq. (1) were determined using available isothermal compression data, [32][33][34][35] together with the measured shock wave profiles. 19 For the specific heat, the constants A, B and 0 θ were determined by fitting the available heat capacity data 36 using Eqs.…”

Superhard sp2–sp3 hybrid carbon allotropes with tunable electronic properties

“…Another little understood carbon allotrope is a transparent superhard carbon polymorph. It is observable under a high pressure range of 10-25 GPa, [15][16][17][18][19][20][21] but only quenchable at low temperatures (<100 K) and at ambient pressure. 15 This post-graphite phase has been extensively explored to identify candidate crystal structures, including sp 2 -sp 3 hybrid (3,0)/(4,0), 22 and sp 3 -hybridized M-carbon, bct-C 4 , F-carbon, X-carbon, Y-carbon, W-carbon, Z-carbon, and P-carbon.…”