MXene is a hot family of transition metal carbides or nitrides demonstrating promising potentials in the fields of batteries, supercapacitors, and memristive devices. One of MXenes, i.e., five-atoms-type MXene (Ti3C2), has been reported to fabricate memristive devices and show resistive switching. However, MXene has another big group of three-atoms-type rather than five-atoms-type based on fundamental chemical structure. Besides, the group of three-atoms-type MXene is rarely investigated to fabricate memristive devices. Moreover, the effect of three-atoms-type Mxene (i.e., V2C) on the performance of memristive devices and the physical mechanisms behind have not been explored. In this work, we constructed the lattice structure and compared the fundamental properties of V2C with Ti3C2 using the first-principles calculation. Moreover, the diffusion coefficient and the conductivity of Ag+ in V2C and Ti3C2 have been checked by the density functional theory (DFT). It can be revealed that V2C has a more stable atomic structure, a higher conductivity, and a superior diffusion coefficient of Ag+ in V2C. In addition, we fabricated memristive devices of the Ag/V2C/W and Ag/Ti3C2/W based on the simulation results for comparison. Next, electrical characteristics of V2C and Ti3C2 of memristive devices were tested including the variation of device-to-device and cycle-to-cycle, the endurance, and the ratio of Roff/Ron. The experimental data indicate that the memristive devices with V2C have achieved more stable resistive switching behaviors. The results of this work provide a useful guideline and methodology for exploring and determining various types of MXenes in advance of the experimental fabrication of memristive devices.

中文翻译：

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三原子型 MXene V2C 的第一性原理计算和实验研究及其对忆阻器件的影响


MXene 是过渡金属碳化物或氮化物的热门家族，在电池、超级电容器和忆阻器件领域展现出巨大的潜力。据报道，其中一种 MXene，即五原子型 MXene (Ti3C2) 可以制造忆阻器件并表现出电阻切换。然而，基于基本化学结构，MXene还有另一大族三原子型而不是五原子型。此外，三原子型MXene族很少被研究用于制造忆阻器件。此外，三原子型Mxene（即V2C）对忆阻器件性能的影响及其背后的物理机制尚未被探索。在这项工作中，我们构建了晶格结构，并使用第一性原理计算比较了 V2C 与 Ti3C2 的基本性质。此外，利用密度泛函理论（DFT）检验了Ag+在V2C和Ti3C2中的扩散系数和电导率。可以看出，V2C具有更稳定的原子结构、更高的电导率以及Ag+在V2C中的优异扩散系数。此外，我们还根据仿真结果制作了Ag/V2C/W和Ag/Ti3C2/W的忆阻器件进行比较。接下来，测试了忆阻器件的V2C和Ti3C2的电特性，包括器件间和周期间的变化、耐久性以及Roff/Ron比值。实验数据表明，采用V2C的忆阻器件实现了更稳定的阻变行为。这项工作的结果为在忆阻器件的实验制造之前探索和确定各种类型的 MXene 提供了有用的指南和方法。