Displacement of surface arsenic atoms by insertion of oxygen atoms into As–Ga backbonds

Stable and metastable oxide structures resulting from the reaction of GaAs(001)-(2×4) with O atoms are investigated using scanning tunneling microscopy (STM). The relative stabilities of these oxide structures are examined using density functional theory calculations (DFT). STM images show that when GaAs(001)-(2×4) is exposed to O atoms, the O atom will either displace an arsenic atom from its original dimer position by taking its place or …