Aurivillius氧化物薄膜中通过室温氧空位有序化实现巨大可逆电导率切换

中文摘要 AI 辅助

氧空位是氧化物功能特性的核心，但通常以随机分布的点缺陷形式存在，限制了对其集体行为的精确调控。本研究通过温和氮等离子体处理，在单晶Aurivillius相Bi₂WO₆薄膜中实现了室温下长程有序氧空位超结构的形成。这种结构转变解锁了电导率超过9个数量级的巨大可逆调制，同时伴随从透明到黑色的显著光学转变。原子级分辨成像与光谱分析显示，空位在类钙钛矿型氧化钨层内选择性有序排列，形成了原始薄膜中不存在的相干缺陷晶格。氧等离子体处理可去除该空位超结构并恢复初始状态，而后续氮等离子体处理可重构该超结构，实现室温下在不同结构、电子和光学状态间的可重复切换。该现象在另一Aurivillius成员Bi₂MoO₆中也被观察到，表明其在Aurivillius家族中具有普遍性。这些发现为原子级缺陷工程建立了新范式——利用温和等离子体化学构建有序缺陷晶格，为复杂氧化物的可逆特性调控开辟了新途径。

英文摘要

Oxygen vacancies are central to the functionality of oxides, yet they typically exist as randomly distributed point defects, limiting the ability to precisely manipulate their collective behavior. Here, we report the room-temperature formation of a long-range-ordered oxygen-vacancy superstructure in single-crystalline Aurivillius-phase Bi2WO6 thin films via a mild nitrogen-plasma treatment. This structural transformation unlocks a colossal, reversible modulation of electrical conductivity by more than nine orders of magnitude, accompanied by a striking optical transition from transparent to black. Atomic-resolution imaging and spectroscopy reveal that the vacancies selectively order within the perovskite-like tungsten oxide layers, forming a coherent defect lattice that is absent in the pristine film. Oxygen-plasma treatment removes the vacancy superstructure and restores the initial state, whereas subsequent nitrogen-plasma treatment reconstructs it, enabling repeatable room-temperature switching between distinct structural, electronic and optical states. The phenomenon is also observed in another Aurivillius member, Bi2MoO6, suggesting its generality across the Aurivillius family. These findings establish a new paradigm for atomic-scale defect engineering - using gentle plasma chemistry to construct ordered defect lattices, opening avenues for reversible property modulation in complex oxides.

发表机构

• Tsientang Institute for Advanced Study, Zhejiang（浙江大学先进技术研究总院）
• Institute of Plasma Physics, HFIPS, Chinese Academy of Sciences, Hefei（中国科学院合肥物质科学研究院等离子体物理研究所）
• Department of Physics and Materials, The Hong Kong Polytechnic University, Hong Kong（香港理工大学物理与材料系）
• Songshan Lake Materials Laboratory, Dongguan, Guangdong（松山湖材料实验室）
• Institute of Physics, Chinese Academy of Sciences, Beijing（中国科学院物理研究所）

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