Polaronic Resistive Switching in Ceria-Based Memory Devices
Polaronic Resistive Switching in Ceria-Based Memory Devices
复制标题
二氧化铈存储器件中的极化电阻开关
DOI：
10.1002/aelm.201900271
复制
发表时间：
2019-07-22
影响因子：
6.2
通讯作者：
Zhou, Miao
中科院分区：
文献类型：
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作者：
Sun, Lu;Hao, Xiamin;Zhou, Miao
阻性随机存取存储器(RRAM)或忆阻器是下一代纳米电子学的关键部件，它工作在电压控制的低和高阻状态(开/关)。大多数忆阻器都是基于氧化物的，但其潜在的工作机制通常仍不清楚。第一性原理计算表明，在CeO_2中，极化子是作为导电物种来调节电阻转换过程的，而通常认为的氧空位(V-O(2+))对极化子的形成起次要作用。重要的是，极化子及其相关络合物具有较低的形成能(约-0.3 eV)和极小的迁移势垒(约0.1 eV)，以协同作用在CeO2基质中形成导电丝，并在费米能级附近形成较浅的电子态，而V-O(2+)具有更高的迁移能，并且不改变CeO2的绝缘性质。根据V-O(2+)、H-INT(+)/H-SUB(+)(机构氢/替代氢)和极化子络合物的相对稳定性，估算出在开/关态之间的切换场约为3V，这与实验结果一致。所提出的基于极化子的开关机制是通用的，为未来理解和设计超越RRAM的多功能电子纳米器件铺平了道路。
Resistive random access memory (RRAM), or memristors, operating with a voltage-controlled low- and high-resistance state (ON/OFF), are a critical component for next-generation nanoelectronics. Most memristors are based on oxides, but the underlying working mechanism remains generally unclear. Using first-principles calculations, it is revealed that it is polaron that acts as the conducting species to mediate the resistive switching process in CeO2, while the commonly believed oxygen vacancy (V-O(2+)) plays only a secondary role in assisting polaron formation. Importantly, polaron and related complexes have desired low formation energies (approximate to-0.3 eV) and extremely small migration barriers (approximate to 0.1 eV), to synergistically form conductive filaments in the CeO2 matrix with shallow electronic states near Fermi level, while V-O(2+) has a much higher migration energy and does not change the insulating nature of CeO2. A switching field is also estimated of approximate to 3 V between the ON/OFF states from the relative stability of V-O(2+), H-int(+)/H-sub(+) (institutional/substitutional hydrogen) and polaron complexes in reference to Fermi level, which agrees with experiments. The proposed polaron-based switching mechanism is general, paving the way for future understanding and design of multifunctional electronic nanodevices beyond RRAM.