Extended Data Fig. 9: Phonon dispersion relations for Re7N3 calculated within the harmonic approximation. | Nature

Extended Data Fig. 9: Phonon dispersion relations for Re7N3 calculated within the harmonic approximation.

From: Materials synthesis at terapascal static pressures

Extended Data Fig. 9

a, Theoretical pressure P = 102 GPa. b, Experimental volume 136.52 Å3, which corresponds to theoretical pressure ~730 GPa. c, Vibrational spectral function at P ≈ 730 GPa and T = 300 K, calculated using the temperature-dependent effective potential (TDEP) method. The results show that in the harmonic approximation, Re7N3 is unstable at the synthesis pressure (imaginary frequencies are shown below the zero-frequency line). Including anharmonic effects of lattice vibrations removes the dynamical instability at P = 730 GPa (all the branches are real).

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