As the epitaxy of crystalline LaAlO3 has not been realized yet, we investigated the use of a g-Al2O3 buffer layer between the high-k and the substrate. We firstly studied the structural matching of g-Al2O3(0 0 1) with a Si(0 0 1)-pð2 1Þ reconstructed surface. According to experimental data and computations in the density functional theory framework, we found stable interfaces between g-Al2O3 and Si which encounters surface reconstruction changes. These interfaces satisfy the criterion of an insulating buffer layer.