Electrical and mechanical properties variation of Al₂O₃–CaO-CNT(3,3) nanomaterial due to Al vacancy and temperature: DFT approach

Al₂O₃–CaO-CNT(3,3) nanomaterial has demonstrated excellent electrical and mechanical properties in the absence of defects suitable for applications in microelectronics, batteries, and fuel cells. It is impossible to develop materials without the presence of defects. Therefore, this research work was instituted to investigate the electrical and mechanical properties of this nanomaterial in the presence of V_Al defect (a defect with lower formation energy in Al₂O₃) through DFT. The calculations were based on the Perdew, Burke, and Ernzerh (PBE) exchange-correlation functional, which uses the generalized-gradient approximation of an all-electron technique. The nanomaterial's spin-up and spin-down energy gaps (E_G) increased due to the defect, from 0.007 eV to 0.000 eV–0.560 eV and 0.129 eV respectively. However, these values are still lower than that of Al₂O₃, which is widely used as an insulator. The lowest and highest E_G recorded was at 0 °C and 60 °C for spin down, and at 0 °C and 80 °C for spin up respectively. The presence of the defect in the nanomaterial also led to the degradation of some of the mechanical properties majorly along (0-10), where the maximum bulk modulus decreases from 48.73 GPa to 8.40 GPa, the compressibility also increases from 56.82 GPa to 90.68 GPa.