First-principles study of the structural, elastic, vibrational, thermodynamic and electronic properties of the Mo2B intermetallic under pressure
| Autor: | M. Romero, Donald H. Galvan, Raul Escamilla, Raúl W. Gómez, Vivianne Marquina, A. Durán, E. Carvajal, Miguel Cruz-Irisson |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Internal energy Chemistry Phonon Organic Chemistry Intermetallic Thermodynamics 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Heat capacity Analytical Chemistry Inorganic Chemistry symbols.namesake Crystallography Lattice constant Helmholtz free energy 0103 physical sciences symbols 0210 nano-technology Elastic modulus Spectroscopy Debye model |
| Zdroj: | Journal of Molecular Structure. 1125:350-357 |
| ISSN: | 0022-2860 |
| DOI: | 10.1016/j.molstruc.2016.07.004 |
| Popis: | The structural, elastic, vibrational, thermodynamic and electronic properties of the Mo2B intermetallic under pressure are assessed using first-principles calculations based on the generalized gradient approximation (GGA) proposed by Perdew-Wang (PW91). Our results show that the calculated structural parameters at a pressure of zero GPa are in good agreement with the available experimental data. The effect of high pressures on the lattice constants shows that the compression along the c-axis and along the a-axis are similar. The elastic constants were calculated using the static finite strain technique, and the bulk shear moduli are derived from the ideal polycrystalline aggregate. We find that the elastic constants, elastic modulus and hardness monotonically increase as a function of pressure; consequently, the structure is dynamically stable and tends from brittle to ductile behavior under pressure. The Debye temperature θD increases and the so-called Gr u ¨ neisen constant γ decreases due to stiffening of the crystal structure. The phonon dispersion curves were obtained using the direct method. Additionally, the internal energy (ΔE), the Helmholtz free energy (ΔF), the entropy (S) and the lattice contribution to the heat capacity Cv were calculated and analyzed with the help of the phonon dispersion curves. The N(EF) and the electron transfer between the B and Mo atoms increase as a function of pressure. |
| Databáze: | OpenAIRE |
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