Structural stability of carbon in the face-centered-cubic (Fm m) phase

Nucleation and growth studies of crystalline carbon phases at nanoscale.

“…The value of the fcc unit cell parameter obtained from the above calculations was 0.3098 nm, which is in good accord with some of the previous theoretical calculation results (0.3020 -0.3082 nm) [58,59]. For bcc carbon, the obtained lattice parameter was a = 0.2389 nm.…”

“…For bcc carbon, the obtained lattice parameter was a = 0.2389 nm. There is strong evidence indicating that these phases are mechanically unstable at least at atmospheric pressure, however, no evidence exists for the rate of their transformation to relatively stable phases like diamond or graphite [59,159].…”

“…Murrieta et al [59] found that the total energy shows a minimum for isotropic deformation at a = 0.308 nm, but the total energy exhibits a maximum for tetragonal and trigonal deformations. They concluded that the fcc structure is not a true metastable phase, but may possibly be stabilized by influence of a substrate or by impurities.…”

An intermediate fcc Zr state observed in the Cu–Zr–Ni system upon ion beam mixing

“…One can see that the elastic stability criteria given in Eq. (1) are fulfilled by the calculated elastic constants for the fcc Zr, dictating that the total-energy surface reaches a local minimum for the isotropic, tetragonal, and trigonal deformations [18]. Finally, to further evaluate the structural stability of the fcc Zr, the phonon spectra at zero pressure along the high symmetry directions of the Brillouin zone (BZ) and phonon density of state (PDOS) are calculated and exhibited in Fig.…”

On the dynamical stability of ferromagnetic Ru and Os in the bct structure: a first-principles study

“…Regardless of the prediction of a ferromagnetic order in the local minimum of the Bain path for Ru and Os in the bct structure with c/a < 1, a study on the dynamical stability in these materials has not yet been reported to the best of our knowledge. From a theoretical point of view, the stability analysis of a given crystal structure is necessary to evaluate if under small deformations of the lattice, the atoms return to their assumed equilibrium position, which identify a truly metastable phase [1,7,8,9].…”