A-site layer terminated perovskite substrate: NdGaO3

A perovskite single-crystal substrate, ${\mathrm{NdGaO}}_{\mathrm{3}}$ (001), was thermally annealed in air to give an atomically defined surface structure. From analysis with coaxial impact-collision ion scattering spectroscopy, the terminating atomic layer was identified to be ${\mathrm{NdO}}_{\mathrm{1+\delta }}\mathrm{ ,}$ i.e., the A-site oxide monolayer in perovskite ${\mathrm{ABO}}_{\mathrm{3}}.$ This result is contrary to the B-site oxide $({\mathrm{BO}}_{\mathrm{2-\delta }})$ termination observed in other perovskite surfaces, such as wet etched ${\mathrm{SrTiO}}_{\mathrm{3}}$ and ${\mathrm{LaAlO}}_{\mathrm{3}}$ or annealed ${\mathrm{(LaAlO}}_{\mathrm{3}}{\mathrm{)}}_{\mathrm{0.3}}{\mathrm{–(Sr}}_{\mathrm{2}}{\mathrm{AlTaO}}_{\mathrm{6}}{\mathrm{)}}_{\mathrm{0.7}}$ (LSAT).