Electrical triggering of a metal–insulator transition (MIT) often results in the formation of characteristic spatial patterns such as a metallic filament percolating through an insulating matrix or an insulating barrier splitting a conducting matrix. When MIT triggering is driven by electrothermal effects, the temperature of the filament or barrier can be substantially higher than the rest of the material. Using X-ray microdiffraction and dark-field X-ray microscopy, we show that electrothermal MIT triggering leads to the development of an inhomogeneous strain profile across the switching device, even when the material does not undergo a pronounced, discontinuous structural transition coinciding with the MIT. Diffraction measurements further reveal evidence of unique features associated with MIT triggering including lattice distortions, tilting, and twinning, which indicate structural nonuniformity of both low- and high-resistance regions inside the switching device. Such lattice deformations do not occur under equilibrium, zero-voltage conditions, highlighting the qualitative difference between states achieved through increasing temperature and applying voltage in nonlinear electrothermal materials. Electrically induced strain, lattice distortions, and twinning could have important contributions in the MIT triggering process and drive the material into nonequilibrium states, providing an unconventional pathway to explore the phase space in strongly correlated electronic systems.

中文翻译：

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X 射线显微镜揭示了电触发金属-绝缘体转变过程中的局部应变不均匀性


金属-绝缘体转变 (MIT) 的电触发通常会导致形成特征空间图案，例如金属丝渗透绝缘基质或绝缘屏障分裂导电基质。当 MIT 触发由电热效应驱动时，灯丝或屏障的温度可能远高于材料的其余部分。使用 X 射线微衍射和暗场 X 射线显微镜，我们表明电热 MIT 触发会导致开关器件上形成不均匀的应变分布，即使材料没有经历与麻省理工学院。衍射测量进一步揭示了与 MIT 触发相关的独特特征的证据，包括晶格畸变、倾斜和孪生，这表明开关器件内低电阻和高电阻区域的结构不均匀性。这种晶格变形在平衡、零电压条件下不会发生，突出了非线性电热材料中通过升高温度和施加电压所实现的状态之间的质的差异。电致应变、晶格畸变和孪生可能在 MIT 触发过程中发挥重要作用，并驱动材料进入非平衡态，为探索强相关电子系统中的相空间提供非常规途径。