We have used low energy electron microscopy (LEEM) to study the evolution of the surface structure of BaTiO3(001) during the ferroelectric-paraelectric phase transition (120 °C, P4mm-Pm3m). Transient surface structures appear under heating at temperatures slightly above TC. Intersections between polar domain walls and the sample surface persist in the surface layer at 126.0 °C while the bulk has already transformed into the cubic phase. The wall signals are criss-crossed by a second set of stripe patterns with roughly perpendicular orientation at 126.3 °C. These surface patterns coarsen under further heating to 126.9 °C. The LEEM image is dominated in the ferroelectric state by intersections of ferroelastic/ferroelectric 90° walls and the surface. The intersection lines are charged.

中文翻译：

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BaTiO3(001)立方-四方相变过程中表面异常的证据

我们使用低能电子显微镜 (LEEM) 研究了 BaTiO3(001) 在铁电-顺电相变 (120 °C, P4mm-Pm3m) 过程中表面结构的演变。在略高于 TC 的温度下加热时会出现瞬态表面结构。极性畴壁和样品表面之间的交叉点在 126.0 °C 的表面层中持续存在，而主体已经转变为立方相。壁信号由第二组条纹图案纵横交错，在 126.3 °C 时方向大致垂直。这些表面图案在进一步加热至 126.9 °C 时会变得粗糙。LEEM 图像在铁电状态下由铁弹性/铁电 90° 壁和表面的交叉点支配。交叉线是收费的。