Mg on adhesion of Al(111)/3C-SiC(111) interfaces from first principles study

First-principles calculations based on density functional theory (DFT) were performed to investigate the doping Mg on the interfacial bonding of Al(111)/3C-SiC(111) interface. The calculated work of adhesion suggests that the Si-terminated and C-terminated interface yields the largest W-ad value of 1.86 J/m(2) and 3.46 J/m(2) at Top-site, respectively. The calculated results of interface energy gamma(int) of Si-terminated and C-terminated Al(111)/3C-SiC(111) interfaces were -0.63 J/m(2) and -0.24 J/m(2), respectively, implying that there was an inter-diffusion between interfacial atoms. The doping of Mg increased the W-ad value of Si-terminated interface from 1.86 J/m(2) to 3.07 J/m(2) and decreased the W-ad value of C-terminated interface from 3.46 J/m(2) to 3.10 J/m(2), suggesting that the doping Mg has the opposite effect on the bonding of these two interfaces. The calculation of the electronic structure showed that interfacial bonding of these two terminated interfaces was a mixture of covalent, ionic and metallic bonds. The doping of Mg enhances the covalent bonding strength of Si-Al bonding states for Si-Mg bond and anti-bonding states for C-Mg bond, respectively. It can be concluded that the doping of Mg was beneficial to the bonding of the Si-terminated interface, but exhibited a negative effect on the binding of C-terminated interface. (C) 2019 Elsevier B.V. All rights reserved.