First-principles calculations to investigate structural and opto-electronic properties of TM2AlC (TM=Cr, Mo) ternary ceramic-metal phases

Abstract

With its outstanding resistance to high temperatures and oxidation, the MAX phase stands out as a highly promising material for high-temperature ceramic materials. To deepen the understanding of the physical properties of Cr₂AlC and Mo₂AlC ternary cermet phases and to provide theoretical support for their applications, structural stability, electronic and optical properties were calculated by the first-principles calculation to design and investigate the TM₂AlC (TM = Cr, Mo) compounds within the M₂AX phase. It reveals that the formation enthalpy of Cr₂AlC and Mo₂AlC are −0.186 and −0.198eV/atom, respectively, indicating that they are both stable and Cr₂AlC exhibiting higher stability. Band structure and bonding analysis demonstrated that TM₂AlC exhibits strong C-TM covalent bonds and metallic properties. Finally, the optical properties such as dielectric constant, and absorption coefficient of Cr₂AlC and Mo₂AlC were studied. The results indicated that both Cr₂AlC and Mo₂AlC are optically anisotropic, which makes them potentially suitable for applications in various optical components, such as absorbers and polarizers. Moreover, their dielectric function ε₁(0) are 59.517 and 42.620, respectively.