First-principles calculations on mechanical and electronical properties of AlB[formula omitted]-type CaB[formula omitted]

Abstract

In the present study, we focused on studying the properties of CaB2 in the hexagonal AlB2-phase. To determine the characteristics of the material, it is crucial to use first-principles calculation methods. Therefore, we used the Density Functional Perturbation Theory to calculate the elastic constants, phonon frequencies, and electron–phonon coupling properties of CaB2, which are important for understanding its superconducting and mechanical behaviors. Additionally, we analyzed Fermi surfaces and electronic band structures and compared them to those of MgB2. Our calculations showed that there is a close relationship between electron–phonon coupling and the superconducting properties of the material. We discovered that the critical superconducting transition temperature value is 24.71 K. In a remarkable finding, the presence of a Dirac cone at the Fermi level was observed in the electronic band structure, which may indicate that the material may be a topological semi-metal.