Two-dimensional (2D) ferroelectric materials exhibit significant potential for applications in nonvolatile memory and device miniaturization. In the device design stage, it is essential to consider the compatibility between 2D ferroelectric materials and three-dimensional (3D) metal. However, the interface between them introduces complex interactions that could impact the device's performance. In this work, based on the first-principles method, we simulate several 3D metal–2D ferroelectric material contact systems by utilizing different 3D metals in contact with the 2D ferroelectric monolayer CuInP2S6 (CIPS). By calculating the electronic structures of the systems, we find that the Cd(001)–CIPS configuration is the most stable structure, followed by the Ag(111)–CIPS and Au(111)–CIPS systems. Both the Cd(001)–CIPS and Ag(111)–CIPS systems undergo a transition from Schottky to Ohmic contact. Finally, we theoretically design a ferroelectric tunnel junction (FTJ) based on the Cd(001)–CIPS contact system, achieving a tunneling electroresistance ratio of 2.394×105% and a remarkably low resistance–area product of 0.78 Ω·μm2, which makes the proposed FTJ superior to the conventional 3D FTJ. This work provides some insights for the design of nonvolatile storage devices.

中文翻译：

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单层铁电材料CuInP2S6金属接触的理论研究及其器件应用


二维（2D）铁电材料在非易失性存储器和设备小型化方面展现出巨大的应用潜力。在器件设计阶段，必须考虑2D铁电材料与三维（3D）金属之间的兼容性。然而，它们之间的接口引入了复杂的交互，可能会影响设备的性能。在这项工作中，基于第一性原理方法，我们利用不同的3D金属与2D铁电单层CuInP2S6（CIPS）接触来模拟几种3D金属-2D铁电材料接触系统。通过计算体系的电子结构，我们发现Cd(001)-CIPS构型是最稳定的结构，其次是Ag(111)-CIPS和Au(111)-CIPS体系。 Cd(001)-CIPS 和 Ag(111)-CIPS 系统都经历了从肖特基接触到欧姆接触的转变。最后，我们从理论上设计了一种基于Cd(001)-CIPS接触系统的铁电隧道结(FTJ)，实现了2.394×105%的隧道电阻比和0.78 Ω·μm2的极低电阻面积积，这使得所提出的 FTJ 优于传统的 3D FTJ。这项工作为非易失性存储设备的设计提供了一些见解。