Ab initio study of thermodynamic properties of bulk zinc-blende CdS: Comparing the LDA and GGA

作者：Baghsiyahi Fatemeh Badieian^*; Akhtar Arsalan; Yeganeh Mahboubeh

来源：International Journal of Modern Physics B, 2018, 32(20): 1850207.

DOI：10.1142/S0217979218502077

• Density functional perturbation theory
• vibrational properties
• phonon dispersion
• Gruneisen parameter
• volume thermal expansion coefficient

In the present study, we have investigated the phonon and thermodynamic properties of bulk zinc-blende CdS by first-principle calculations within the density functional theory (DFT) and the density functional perturbation theory (DFPT) method using the quasi harmonic approximation (QHA). We calculated the phonon dispersion at several high symmetry directions, density of phonon state, temperature dependence feature of Helmholtz free energy (F), internal energy, bulk modulus, constant-volume specific heat, entropy, coefficient of the volume thermal expansion and Gruneisen parameter estimated with the local density approximation (LDA) and generalized gradient approximation (GGA) for the exchange-correlation potential and compared them with each other. For internal energy, Helmholtz free energy, constant volume heat capacity and phonon entropy the LDA and GGA results are very similar. But, the LDA gives lattice constants that are smaller than GGA while phonon frequencies, bulk modulus and cohesive energies are larger. On the other hand, the results obtained through the GGA approximation for the coefficient of the volume thermal expansion and Gruneisen parameter are larger than those obtained from LDA.

• 出版日期2018-8-10