Cu₂S has been identified as a functional material of memristors with multilevel resistance switching. However, as the migration of Cu ions under the electric field is tangled with defect evolution and phase transition, the electroresistance mechanism of Cu₂S remains largely unclear. Here, the electrically triggered phase transition was studied by in situ transmission electron microscopy. It is found that the γ(L)-Cu₂S phase is transformed into β-Cu₂S accompanied by the change in resistance, when a voltage lower than 1 V is applied at room temperature. The electrically triggered phase transition is also observed at −150 °C. Precipitation of metal Cu nanoparticles is observed when the applied voltage is further increased after the complete formation of β-Cu₂S. These findings indicate that Cu₂S can achieve fast and controllable phase switching through electrical tuning when the energy consumption is appropriately controlled, offering the potential for low-power electronic devices such as memory and sensors.

中文翻译：

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薄 Cu2S 晶体中电触发相变的原位观测


Cu₂S 已被确定为具有多级电阻开关的忆阻器的功能材料。然而，由于 Cu 离子在电场下的迁移与缺陷演化和相变纠缠在一起，Cu₂S 的电阻机制在很大程度上仍不清楚。在这里，通过原位透射电子显微镜研究了电触发相变。研究发现，当在室温下施加低于 1 V 的电压时，γ（L）-Cu₂S 相会随着电阻的变化转变为 β-Cu₂S。在 −150 °C 时也可以观察到电触发相变。 在 β-Cu₂S 完全形成后，当施加的电压进一步增加时，观察到金属 Cu 纳米颗粒的沉淀。这些发现表明，在能耗得到适当控制的情况下，Cu₂S 可以通过电气调谐实现快速可控的相位切换，为存储器和传感器等低功耗电子设备提供了潜力。