Fe/Fe₃O₄ core–shell-cluster-assembled nanostructured films were prepared using the low-energy cluster beam deposition technique. The temperature-dependent resistivity behaviors were investigated for the films with changing core-occupation ratio of clusters. Much interestingly and surprisingly, a switchable metal–insulator transition can be observed, featuring the rapid switching from the metal state to the insulation state and then back to the metal state, for films within a specific range of core-occupation ratio. Further, the resistivity change rate used to characterize the metal–insulator transition can reach as high as two orders of magnitude over a very narrow temperature region. The design of Fe/Fe₃O₄ core–shell clusters plays a decisive role in the mechanism of the switchable metal–insulator transition in these films. The assembled core–shell clusters in the films form current conduction channels that are switchable between the cores and shells of clusters as the temperature changes. The switching of the current conduction channels can be regulated by controlling the core-occupation ratios of clusters, which induce a switchable metal–insulator transition and can be verified by the effective medium theory over a specific core-occupation ratio range.

中文翻译：

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核-壳簇组装纳米结构薄膜中的可切换金属-绝缘体转变。

Fe / Fe ₃ O ₄核－壳－团簇组装纳米结构薄膜是采用低能簇束沉积技术制备的。研究了随团簇核心占有率变化的薄膜的温度依赖性电阻率行为。有趣且令人惊讶的是，可以观察到可切换的金属-绝缘体转变，其特征是在特定的芯占有率范围内，薄膜会从金属态快速转变为绝缘态，然后又回到金属态。此外，用于表征金属-绝缘体转变的电阻率变化率可以在非常狭窄的温度区域内达到两个数量级。Fe / Fe ₃ O _4的设计核-壳簇在这些薄膜的可切换金属-绝缘体转变机理中起着决定性作用。膜中组装的核-壳簇形成电流传导通道，随着温度的变化，可以在簇的核和壳之间切换。可以通过控制簇的核心占有率来调节电流传导通道的切换，这会引起金属-绝缘体的转换，并且可以通过有效介质理论在特定的核心占有率范围内进行验证。