Substrate-induced band structure and electronic properties in graphene/Al2O3(0001) interface

Band structure investigation results of two-dimensional (2D) graphene (SLG) on Al2O3(0001) using the density functional theory (DFT) method as a possible element base for spintronics are presented. Regularities of a band structure change in the order three-dimensional (3D) Al2O3 → 2D Al2O3(0001) → 2D SLG/Al2O3(0001) as well as features of a chemical bond between SLG and sapphire on the basis of DFT calculations have been studied. Analysis of the band structure and interatomic spacing in the interface for both models allows speaking about physical SLG adsorption on the (0001)-surface sapphire constrained by aluminum atoms. Energy distribution features of surface states in 2D SLG/Al2O3(0001) interface are discussed. Analysis of effective atomic charge in the interface revealed surface charge fluctuations on the substrate in the presence of SLG, which can be explained by a decrease of the energy of occupied subsurface Al2O3 states relatively to the Fermi level.