Effect of the stoichiometry on the electronic structure of the Ni(111)/α-Al2O3(0001) interface:a first-principles investigation

In this paper first-principles calculations of Ni(111)/α-Al2O3 (0001) interfaces have been performed,and are compared with the preceding results of the Cu (111)/α-Al2O3 (0001) interface [2004 Phil. Mag. Lett. 84425]. The Al-terminated and O-terminated interfaces have quite different adhesion mechanisms,which are similar to the Cu(111)/α-Al2O3 (0001) interface. For the O-terminated interface,the adhesion is caused by the strong O-2p/Ni-3d orbital hybridization and ionic interactions. On the other hand,the adhesion nature of the Al-terminated interface is the image-like electrostatic and Ni-Al hybridization interactions,the latter is substantial and cannot be neglected. Charge transfer occurs from Al2O3 to Ni,which is opposite to that in the O-terminated interface. The charge transfer direction for the Al-terminated and O-terminated Ni(111)/α-Al2O3 (0001) interfaces is similar to that in the corresponding Cu(111)/α-Al2O3 (0001) interface,but there exist the larger charge transfer quantity and consequent stronger adhesion nature,respectively.