Structure and bonding properties of Y doped \Sigma37 grain boundary in alumina

The microscopic structures and the bonding properties of Y-doped and undoped (01\bar 18)/04\bar 41/180^\circ (\Sigma 37) grain boundaries in alumina are investigated by using ab initio method. The formation energy of grain boundary and the segregation energy of Y to grain boundary are acquired. Electronic structures, potential distributions, bond orders and effective charges of Y-doped and undoped \Sigma 37 GB systems are calculated. Our results reveal that the higher strength Y--O bond than Al--O bond is ascribed to the hybridization of Y(4p, 3d) with O(2s). Meanwhile, dopant Y also causes a change in potential distribution in the grain boundary region, thereby further affecting the transport property of ceramic alumina.