Structural and Electronic Properties of the Interface between the High-k oxide LaAlO3 and Si(001)

TL;DR

This study uses advanced electronic structure calculations to analyze the LaAlO3/Si(001) interface, revealing new atomic structures, stability conditions, and implications for its use as a gate dielectric.

Contribution

It provides a revised atomic structure model and stability phase diagram, questioning LaAlO3's suitability as an epitaxial gate dielectric.

Findings

Atomic structure differs from previous models

Electronically saturated interface requires dopant segregation

Raises doubts about LaAlO3 as a gate dielectric

Abstract

The structural and electronic properties of the LaAlO3/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 dopant atoms segregate to the interface. These findings raise serious doubts whether LaAlO3 can be used as an epitaxial gate dielectric.