Nanoscale structural variation observed on the vicinal SrTiO3(001) surface
Nanoscale structural variation observed on the vicinal SrTiO3(001) surface
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DOI：
10.1063/1.3447796
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发表时间：
2010-06
影响因子：
4
通讯作者：
S. Shiraki;M. Nantoh;S. Katano;M. Kawai
中科院分区：
文献类型：
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作者：
S. Shiraki;M. Nantoh;S. Katano;M. Kawai
通过扫描隧道显微镜和低能电子衍射研究了 Nb 掺杂 SrTiO3 单晶的邻位 (001) 表面。通过在 250 °C 超高真空中退火制备的阶梯表面表现出由四种类型的重构组成的复杂原子结构，显示出纳米级区域内的短程变化。 SrO层显示出c(6×2)结构在1000℃下保持稳定，而在TiO2层上形成√13×√13-R33.7°、c(√13×√13)-R33.7°和c(√2×√18)-R45°结构，这些结构在450-750℃时消失，随后形成2×2和√5×√5-R26.6°结构。这些结果表明，与热力学稳定的 SrO 封端表面相比，由于多运动过程引起的 Sr 吸附原子密度变化，TiO2 封端表面上的重建不稳定。
The vicinal (001) surface of a Nb-doped SrTiO3 single crystal has been investigated by scanning tunneling microscopy and low energy electron diffraction. The stepped surface prepared by annealing in ultrahigh vacuum at 250 °C exhibits a complex atomic structure composed of four types of reconstructions, which shows short-range variation within nanoscale regions. SrO layers show a c(6×2) structure being stable up to 1000 °C, while √13×√13-R33.7°, c(√13×√13)-R33.7°, and c(√2×√18)-R45° structures are formed on TiO2 layers, which disappear at 450–750 °C followed by the formation of 2×2 and √5×√5-R26.6° structures. These results indicate instability of the reconstructions on the TiO2 terminated surface due to the variation in Sr adatom density caused by multikinetic processes, in contrast to the thermodynamically stable SrO terminated surface.