氧化物结中纳米尺度原位电场映射：关联STEM-EBIC与4D-STEM

中文摘要 AI 辅助

理解氧化物界面处的局域电场对于将界面静电学与器件功能联系起来至关重要，然而传统的电学测量仅能间接推断这些电场。在此，我们将操作态扫描透射电子显微镜电子束诱导电流（STEM-EBIC）与四维扫描透射电子显微镜（4D-STEM）相结合，在纳米尺度上定量重构氧化物肖特基结中随偏压变化的电场空间分布。以La0.67Sr0.33MnO3/Nb:SrTiO3（LSMO/NSTO）作为模型体系，我们在MEMS偏置平台上制备了电子透明的结，并验证其保留了整流输运行为。STEM-EBIC提供了互补信息，解决了异质结定量4D-STEM电场映射中的若干关键限制。重构的电场分布显示出耗尽区内显著的非线性衰减以及向LSMO内部的延伸穿透。这些结果直接揭示了氧化物肖特基结偏离理想常规肖特基耗尽模型的现象，提供了非经典界面静电学的实验特征。我们的关联方法能够在工作状态下的氧化物异质结中进行定量纳米尺度电场映射，为将界面静电学与宏观输运联系起来以及指导氧化物器件设计提供了基础。

英文摘要

Understanding local electric fields at oxide interfaces is essential for linking interfacial electrostatics to device functionality, yet conventional electrical measurements infer these fields only indirectly. Here, we combine operando scanning transmission electron microscope electron-beam-induced current (STEM-EBIC) with four-dimensional-STEM (4D-STEM) to quantitatively reconstruct the bias-dependent electric field spatial distribution across an oxide Schottky junction at nanometer scale. Using La0.67Sr0.33MnO3/Nb:SrTiO3 (LSMO/NSTO) as a model system, we fabricate an electron-transparent junction on a MEMS biasing platform and verify that it retains the rectifying transport behavior. STEM-EBIC provides complementary information addressing several key limitations in quantitative 4D-STEM field mapping for heterojunctions. The reconstructed electric field profiles show a pronounced nonlinear decay within the depletion region and an extended penetration into the LSMO. These results directly reveal the deviations of oxides Schottky junction from the ideal conventional Schottky depletion model, providing experimental signatures of non-classical interfacial electrostatics. Our correlative approach enables quantitative nanoscale electric field mapping in operating oxide heterojunctions, providing a basis for linking interfacial electrostatics to macroscopic transport and guiding oxide devices design.

发表机构

• University of Warwick（华威大学）
• The University of Science and Technology of China（中国科学技术大学）
• Hefei National Laboratory（合肥国家实验室）

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