Reconstructions on SrTiO3(111) surface tuned by Ti/Sr deposition

The reconstruction of SrTiO3(111) polar surface is investigated by scanning tunneling microscopy (STM) and electron diffractions. The (4 × 4), (6 × 6) and (5 × 5) reconstructions are prepared, and the evolution between them can be reversely controlled by adjusting the deposition dosage of Sr or Ti. Based on the STM height analysis and the optimal deposition dosage to obtain the monophased reconstructions, we conclude that the (4 × 4) reconstruction is based on SrO3 termination while the (6 × 6) and (5 × 5) are based on Ti termination. Their different polar compensation mechanisms as well as adsorption behaviors are also discussed.