发表机构
University of Wisconsin-Madison; Southern University of Science and Technology（威斯康星大学麦迪逊分校; 南方科技大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过第一性原理计算揭示SrTiO3和Sr2TiO4薄膜MBE生长中氧空位加速扩散、TiSr缺陷促进SrO岛形成及Ti/TiO2插入SrO双层等机制，为金属氧化物薄膜生长控制提供指导。
AI 中文摘要
分子束外延（MBE）以其原子层控制的潜力而闻名，但意外的生长机制可能潜在地损害这种精度水平。在本研究中，我们采用第一性原理计算来研究控制钙钛矿SrTiO3和Ruddlesden-Popper Sr2TiO4薄膜在SrTiO3衬底上MBE生长的原子级过程。我们系统地探索了气相中潜在的分子种类及其在薄膜表面和层边缘上的反应和扩散动力学。我们的分析揭示了三个对理解此类生长至关重要的机制。首先，在无缺陷衬底上的表面扩散过程中，氧空位可以被动态诱导，并显著加速扩散过程。其次，虽然SrO层预期以单层生长模式生长，但潜在TiSr缺陷的存在可能促进SrO岛的形成。最后，吸附在SrO双层上的Ti原子和TiO2分子可以插入SrO双层中，导致意外的生长顺序。这些发现可能对金属氧化物薄膜的MBE生长具有更广泛的意义，并为实现对其生长过程的更好控制提供指导。
英文摘要
Molecular beam epitaxy (MBE) is renowned for its potential for atomic layer control, but unexpected growth mechanisms can potentially compromise this level of precision. In this study, we employ first-principles calculations to investigate the atomistic processes governing the MBE growth of perovskite SrTiO3 and Ruddlesden-Popper Sr2TiO4 films on a SrTiO3 substrate. We systematically explore the potential molecular species in the gas phase and their reactions and diffusion dynamics on the film surfaces and layer edges. Our analyses uncover three mechanisms of importance for understanding this type of growth. First, oxygen vacancies can be dynamically induced during surface diffusion on defect-free substrate and noticeably accelerate the diffusion processes. Second, while the SrO layer is expected to grow in a single-layer growth mode, the presence of potential TiSr defects may promote the formation of SrO islands. Lastly, adsorbed Ti atoms and TiO2 molecules on the SrO bilayer can insert into SrO bilayers, resulting in an unexpected growth sequence. These findings may have broader implications for the MBE growth of metal oxide films and provide guidance for achieving improved control over their growth processes.
Comments21 pages, 15 figures
Journal refPhysical Review Materials 10, 083405 (2026)
