In search of new reconstructions of (001) α-quartz surface: a first principles study

Using Born-Oppenheimer molecular dynamics (BOMD) simulations and static density functional theory (DFT) calculations, the stability of cleaved and reconstructed alpha-SiO2(001) surfaces was studied. We found reconstructions (dense, 2 x 2 reoptimized dense, and 3 x 3 reoptimized dense) which minimize the surface energy. The analysis of the surface energies shows that the cleaved surface reconstructs to the 2 x 2 reoptimized dense surface having a surface energy around 10% smaller than the dense surface. The results suggest that the optimization of Si-Si and Si-O distances at top surface layers plays the key role in stabilizing the 2 x 2 dense surface over the well-known dense surface.