Author Affiliations
1State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China2Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, School of Physics and Engineering, Henan University of Science and Technology, Luoyang 471023, People’s Republic of China3Laboratory of High Pressure Physics and Material Science (HPPMS), School of Physics and Physical Engineering, Qufu Normal University, Qufu, Shandong 273165, People’s Republic of Chinashow less
Fig. 1. (a) Formation enthalpies ΔH of various CeNn (n = 0.5, 1, 2, 3, 4, 5, and 6) compounds under high pressure. The stable phases are connected by solid lines and unstable/metastable phases by dashed lines. (b) Pressure–composition phase diagram of the predicted Ce–N phases.
Fig. 2. (a) Crystal structure of P1̄-CeN6 at 32 GPa. (b) Nitrogen structural skeleton of P1̄-CeN6 at 32 GPa. The independent N atoms are marked as N1, N2, and N3 in the symmetric N14 rings. (c) Phonon dispersion curve and PHDOS of P1̄-CeN6 at 32 GPa. (d) Initial and terminal structures in AIMD simulations with total simulation time 10 ps and fluctuations of the total energy of P1̄-CeN6 at 32 GPa and 300 K.
Fig. 3. (a) ELF of P1̄-CeN6 (isovalue = 0.8). (b) The charge transfer and formation energy of CeNn (n = 1, 2, 3, 4 and 6) compounds at 32 GPa.
Fig. 4. (a) Crystal structure, (b) −pCOHP and −ICOHP, and (c) PDOS of N2 molecular crystal. (d) Crystal structure, (e) −pCOHP and −ICOHP, and (f) PDOS of trans-CeN6. (g) Crystal structure, (h) −pCOHP and −ICOHP, and (i) PDOS of P1̄-CeN6 at 32 GPa.
Fig. 5. (a) Phonon dispersion curve and PHDOS of P1̄-CeN6 at 0 GPa. (b) RDFs g(r) and structures of final states from the last 2 ps of AIMD simulations at ambient pressure and temperatures of 300 K (solid lines) and 1000 K (dotted lines). (c) PDOS of P1̄-CeN6 at 0 GPa. (d) Curves of charge transfer and enthalpy as functions of pressure during pressure release in P1̄-CeN6, with the enthalpy of P1̄-CeN6 at 32 GPa being taken as the reference zero point.
Fig. 6. (a) 3D surface and (b) 2D projected profiles of Young’s modulus in P1̄-CeN6.
Compound | ρ (g/cm3) | Ed (kJ/g) | Ev (kJ/cm3) | Vd (km/s) | Pd (GPa) |
---|
-CeN6 | 5.60 | 2.00 | 11.20 | 13.60 | 128.95 | TNT | 1.64a | 4.30b | 7.05c | 6.90d | 19.00a | HMX | 1.90a | 5.70b | 10.83c | 9.10d | 39.30a |
|
Table 1. Mass density ρ, mass energy density Ed, volumetric energy density Ev, detonation velocity Vd, and detonation pressure Pd of -CeN6 compared with those of TNT and HMX.
B (GPa) | G (GPa) | E (GPa) | ν | Hv (GPa) | B/G |
---|
155.00 | 118.12 | 282.59 | 0.20 | 20.73 | 1.31 |
|
Table 2. Bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s ratio ν, and Vickers hardness Hv of -CeN6.