In-situ diffuse neutron scattering experiments revealed that when electric current is passed through single crystals of rutile TiO2 under conditions conducive to flash sintering, it induces the formation of parallel planes of oxygen vacancies. Specifically, a current perpendicular to the c-axis generates planes normal to the (132) reciprocal lattice vector, whereas currents aligned with the c-axis form planes normal to the (132) and to the (225) vector. The concentration of defects increases with incresing current. The structural modifications are linked to the appearance of signatures of interacting Ti3+ moments in magnetic susceptibility, signifying a structural collapse around the vacancy planes. Electrical conductivity measurements of the modified material reveal several electronic transitions between semiconducting states (via a metal-like intermediate state) with the smallest gap being 27 meV. Pristine TiO2 can be restored by heating followed by slow cooling in air. Our work suggests a novel paradigm for achieving switching of electrical conductivity related to the flash phenomenon.

中文翻译：

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电流诱导的 TiO2 的结构和电子转变


原位漫射中子散射实验表明，当电流在有利于闪烧的条件下通过金红石型 TiO2 的单晶时，它会诱导形成平行的氧空位平面。具体来说，垂直于 c 轴的电流产生垂直于 （132） 倒易晶格矢量的平面，而与 c 轴对齐的电流形成垂直于 （132） 和 （225） 矢量的平面。缺陷的浓度随着电流的增加而增加。结构修改与磁化率中相互作用的 Ti3+ 矩的特征的出现有关，这意味着空位面周围的结构坍缩。改性材料的电导率测量揭示了半导体状态之间的几个电子跃迁（通过类似金属的中间态），最小的间隙为 27 meV。原始的 TiO2 可以通过加热然后在空气中缓慢冷却来恢复。我们的工作提出了一种新的范式，用于实现与闪光现象相关的电导率切换。