Department of Material Science and Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
Université Paris-Saclay, CNRS Laboratoire de Physique des Solides, 91405, Orsay, France.
Science. 2021 Aug 20;373(6557):907-911. doi: 10.1126/science.abd9088. Epub 2021 Jul 22.
Many correlated systems feature an insulator-to-metal transition that can be triggered by an electric field. Although it is known that metallization takes place through filament formation, the details of how this process initiates and evolves remain elusive. We use in-operando optical reflectivity to capture the growth dynamics of the metallic phase with space and time resolution. We demonstrate that filament formation is triggered by nucleation at hotspots, with a subsequent expansion over several decades in time. By comparing three case studies (VO, VO, and VO), we identify the resistivity change across the transition as the crucial parameter governing this process. Our results provide a spatiotemporal characterization of volatile resistive switching in Mott insulators, which is important for emerging technologies, such as optoelectronics and neuromorphic computing.
许多关联系统都具有可以通过电场触发的绝缘到金属的转变。尽管人们知道金属化是通过细丝形成发生的，但这一过程如何开始和演变的细节仍然难以捉摸。我们使用实时光学反射率来以空间和时间分辨率捕捉金属相的生长动力学。我们证明，细丝形成是由热点处的成核引发的，随后在数十个时间尺度上扩展。通过比较三个案例研究（VO、VO 和 VO），我们确定了转变过程中的电阻率变化是控制这一过程的关键参数。我们的结果为 Mott 绝缘体中易挥发的电阻开关提供了时空特征，这对于新兴技术（如光电和神经形态计算）非常重要。
