School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China.
Hunan Key Laboratory for Micro-nano Energy Materials and Devices, Xiangtan University, Hunan 411105, China.
Nanoscale. 2023 Mar 30;15(13):6363-6370. doi: 10.1039/d2nr05344f.
Low-dimensional ferroelectric materials, the mainstay of current high-density non-volatile memory devices, sensors, and nanoscale electronics, have attracted tremendous attention recently. Through employing an evolutionary algorithm and first-principles calculations, we report three novel and stable two-dimensional (2D) ferroelectric materials δ-AsN, δ-SbN, and δ-BiN with spontaneous polarization of up to 5.72 × 10, 5.20 × 10, and 4.45 × 10 C m, respectively. The molecular dynamics (AIMD) simulations further show that the failure temperature of ferroelectricity of δ-AsN, δ-SbN, and δ-BiN is as high as 2000 K, 2000 K, and 1700 K, demonstrating their strong robustness. More interestingly, the three novel materials also exhibit extraordinary piezoelectricity with relaxation ion piezoelectric coefficients of 5.39, 19.55, and 43.87 pm V, respectively. The external strain effect found can effectively modulate their spontaneous polarization, ferroelectric switching energy barrier, and piezoelectric properties. These fascinating ferroelectricity and piezoelectricity features endow δ-AsN, δ-SbN, and δ-BiN with significant potential application in future miniaturized and integrated multi-functional electronic devices.
低维铁电材料是当前高密度非易失性存储器件、传感器和纳米尺度电子学的主要研究方向，最近引起了极大的关注。通过采用进化算法和第一性原理计算，我们报道了三种新型且稳定的二维（2D）铁电材料 δ-AsN、δ-SbN 和 δ-BiN，其自发极化强度分别高达 5.72×10、5.20×10 和 4.45×10 C m。分子动力学（AIMD）模拟进一步表明，δ-AsN、δ-SbN 和 δ-BiN 的铁电失效温度高达 2000 K、2000 K 和 1700 K，表现出很强的稳定性。更有趣的是，这三种新型材料还表现出非凡的压电性能，弛豫离子压电系数分别为 5.39、19.55 和 43.87 pm V。发现的外部应变效应可以有效地调节它们的自发极化、铁电极化开关能垒和压电性能。这些迷人的铁电性和压电性能使 δ-AsN、δ-SbN 和 δ-BiN 在未来的小型化和集成多功能电子器件中有重要的潜在应用。
