Direct determination of a topmost atomic layer of (100) surfaces on (La0.3Sr0.7)(Al0.65Ta0.35)O3 single crystals annealed in air by high-resolution scanning transmission electron microscopy |
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| Authors: | Yoshinori Tokuda Takeshi Irimoto Naoki Nishikawa Yutaro Katsuyama Shunsuke Kobayashi Tomoharu Tokunaga Takahisa Yamamoto |
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| Institution: | 1. Department of Materials Design Innovation Engineering, Nagoya University, Nagoya, Japan;2. Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, Japan |
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| Abstract: | Herein, we investigated the surface of an (La0.3Sr0.7)(Al0.65Ta0.35)O3 (LSAT) single crystal via scanning transmission electron microscopy (STEM) after annealing in air. We found amorphous mounds and atomically flat surfaces formed on the surface of the (100) LSAT single crystal subsequent to heat treatment. These surface mounds mainly constituted SrO, including ~50 at.% Al. The atomically flat surface showed a B-site termination determined by the direct surface observation at the atomic scale through HAADF-STEM. The atomic arrangements on the surface were accommodated by surface-mound formation and La evaporation. Consequently, the ordered structure disappeared because of the increase in the Ta content at the terminated B-site layer. |
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| Keywords: | HAADF-STEM LSAT single crystals step-terrace structure terminated layer |
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