Sahu Mousam Charan, Mallik Sameer Kumar, Sahoo Sandhyarani, Gupta Sanjeev K, Ahuja Rajeev, Sahoo Satyaprakash
Laboratory for Low Dimensional Materials, Institute of Physics, Bhubaneswar 751005, India.
Homi Bhaba National Institute, Mumbai 400094, India.
J Phys Chem Lett. 2021 Feb 25;12(7):1876-1884. doi: 10.1021/acs.jpclett.1c00121. Epub 2021 Feb 15.
The recent observation of stable quantized conductance in anatase TiO resistive random access memory (ReRAM) devices opens up a new pathway toward the realization of brain-inspired neuromorphic computing devices. Herein, for the first time, ab initio calculations are implemented to understand the resistive switching phenomena in anatase TiO. Oxygen vacancy configurations with different charge states are studied to gain insight into the ON and OFF states of ReRAM devices. Among the trivacancy configurations, the V state is observed to induce highly dispersed defect states within the bandgap forming a charge density channel where the carriers behave as free electrons leading to the formation of a conducting filament (CF). On the contrary, the breakdown of the CF is noticed by the removal of an oxygen vacancy from the trivacancy configuration. In this OFF state, the defect state carriers are found to be highly localized. In addition, we have also investigated the effect of charge injection on the crystal field symmetry of the CF. The reduction of symmetry due to the trivacancy configuration lowers the e manifold energy, whereas the divacancy configuration lowers the t manifold energy.
最近在锐钛矿型TiO₂电阻式随机存取存储器（ReRAM）器件中观察到稳定的量子化电导，为实现受大脑启发的神经形态计算器件开辟了一条新途径。在此，首次进行了从头算计算，以了解锐钛矿型TiO₂中的电阻开关现象。研究了具有不同电荷状态的氧空位构型，以深入了解ReRAM器件的开态和关态。在三空位构型中，观察到V态在带隙内诱导出高度分散的缺陷态，形成一个电荷密度通道，载流子在其中表现为自由电子，导致导电细丝（CF）的形成。相反，通过从三空位构型中去除一个氧空位，可以注意到CF的击穿。在这种关态下，发现缺陷态载流子高度局域化。此外，我们还研究了电荷注入对CF晶体场对称性的影响。由于三空位构型导致的对称性降低会降低e流形能量，而双空位构型会降低t流形能量。
