Structural and electronic properties of the interface between the high-k Oxide LaAlO3 and Si(001)

The structural and electronic properties of the LaAlO(3)/Si(001) interface are determined using state-of-the-art electronic structure calculations. The atomic structure differs from previous proposals, but is reminiscent of La adsorption structures on silicon. A phase diagram of the interface stability is calculated as a function of oxygen and Al chemical potentials. We find that an electronically saturated interface is obtained only if Al atoms substitute some of the interfacial Si atoms. These findings raise serious doubts whether LaAlO3 can be used as an epitaxial gate dielectric.