Ab initio density functional theory study on the atomic and electronic structure of GaP/Si(001) heterointerfaces

Authors/others:Romanyuk, O. (Czech Academy of Sciences); Supplie, O. (Technische Universität Ilmenau); Susi, T.; May, M. M. (University of Cambridge); Hannappel, T. (Technische Universität Ilmenau)
Abstract:The atomic and electronic band structures of GaP/Si(001) heterointerfaces were investigated by ab initio density functional theory calculations. Relative total energies of abrupt interfaces and mixed interfaces with Si substitutional sites within a few GaP layers were derived. It was found that Si diffusion into GaP layers above the first interface layer is energetically unfavorable. An interface with Si/Ga substitution sites in the first layer above the Si substrate is energetically the most stable one in thermodynamic equilibrium. The electronic band structure of the epitaxial GaP/Si(001) heterostructure terminated by the (2 x 2) surface reconstruction consists of surface and interface electronic states in the common band gap of two semiconductors. The dispersion of the states is anisotropic and differs for the abrupt Si-Ga, Si-P, and mixed interfaces. Ga 2p, P 2p, and Si 2p core-level binding-energy shifts were computed for the abrupt and the lowest-energy heterointerface structures. Negative and positive core-level shifts due to heterovalent bonds at the interface are predicted for the abrupt Si-Ga and Si-P interfaces, respectively. The distinct features in the heterointerface electronic structure and in the core-level shifts open new perspectives in the experimental characterization of buried polar-on-nonpolar semiconductor heterointerfaces.
Number of pages:9
Date of publication:18.10.2016
Journal title:Physical Review B (Condensed Matter and Materials Physics)
Peer reviewed:true
Digital Object Identifier (DOI):http://dx.doi.org/10.1103/PhysRevB.94.155309
Publication Type:Article