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<p>Structural and dynamic stability, electronic properties and thermodynamic characteristics of lanthanum carbide, at room pressure, are reported. The calculations are mainly done in local density approximation (LDA) and generalized gradient approximation (GGA) in the framework of the density functional theory (DFT) using the plane wave method in the Quantum Espresso calculation code. The structural results reveal that the compound is harder in LDA approximation in comparison with GGA. The band structure diagrams and the density of states in both approximations showed that the energy bands crossed the Fermi level, which indicates the metal structure for the composition of lanthanum carbide. According to the calculated density of states, it can be concluded that there is ionic bond between this compound’s atoms. The phonon scattering diagrams show that the compound is dynamically stable. Thermodynamic studies show that enthalpy increases with the increase in pressure, slowly and uniformly. Moreover, the increase in entropy, due to the increase in temperature, shows that the process is endothermic. As lattice parameter is smaller in LDA approximation with respect to GGA approximation, it leads to increase in hardness. Furthermore, heat capacity increases with increase in temperature, continuously and converge to Dulong–Petit classic value which is 6R.</p>

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Investigation and Comparison of Structural, Electronic and Thermodynamic Properties of Lanthanum Carbide Compound using GGA and LDA Approximation

  • 期刊论文

  • 发表日期：

    2025年1月24日

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  • A. Aqeel,
  • A. Khajehnezhad,
  • A. Aezami

摘要

Structural and dynamic stability, electronic properties and thermodynamic characteristics of lanthanum carbide, at room pressure, are reported. The calculations are mainly done in local density approximation (LDA) and generalized gradient approximation (GGA) in the framework of the density functional theory (DFT) using the plane wave method in the Quantum Espresso calculation code. The structural results reveal that the compound is harder in LDA approximation in comparison with GGA. The band structure diagrams and the density of states in both approximations showed that the energy bands crossed the Fermi level, which indicates the metal structure for the composition of lanthanum carbide. According to the calculated density of states, it can be concluded that there is ionic bond between this compound’s atoms. The phonon scattering diagrams show that the compound is dynamically stable. Thermodynamic studies show that enthalpy increases with the increase in pressure, slowly and uniformly. Moreover, the increase in entropy, due to the increase in temperature, shows that the process is endothermic. As lattice parameter is smaller in LDA approximation with respect to GGA approximation, it leads to increase in hardness. Furthermore, heat capacity increases with increase in temperature, continuously and converge to Dulong–Petit classic value which is 6R.