Hu Yue, Jiang Jingwen, Zhang Peng, Ma Zhuang, Guan Fuxin, Li Da, Qian Zhengfang, Zhang Xiuwen, Huang Pu
Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, 518060, Shenzhen, China.
School of Information Engineering, Jiangmen Polytechnic, Jiangmen, China.
Nat Commun. 2023 Oct 17;14(1):6555. doi: 10.1038/s41467-023-42312-4.
During the last two decades, two-dimensional (2D) materials have been the focus of condensed matter physics and material science due to their promising fundamental properties and (opto-)electronic applications. However, high-κ 2D dielectrics that can be integrated within 2D devices are often missing. Here, we propose nonlayered oxide monolayers with calculated exfoliation energy as low as 0.39 J/m stemming from the ionic feature of the metal oxide bonds. We predict 51 easily or potentially exfoliable oxide monolayers, including metals and insulators/semiconductors, with intriguing physical properties such as ultra-high κ values, negative Poisson's ratios and large valley spin splitting. Among them, the most promising dielectric, GeO, exhibits an auxetic effect, a κ value of 99, and forms type-I heterostructures with MoSe and HfSe, with a band offset of ~1 eV. Our study opens the way for designing nonlayered 2D oxides, offering a platform for studying the rich physics in ultra-thin oxides and their potential applications in future information technologies.
在过去二十年中，二维（2D）材料因其具有前景的基本特性和（光）电子应用，一直是凝聚态物理和材料科学的焦点。然而，能够集成到二维器件中的高κ二维电介质却常常缺失。在此，我们提出具有非层状结构的氧化物单分子层，由于金属氧化物键的离子特性，其计算得出的剥离能低至0.39 J/m²。我们预测了51种易于或可能剥离的氧化物单分子层，包括金属以及绝缘体/半导体，它们具有诸如超高κ值、负泊松比和大的能谷自旋分裂等引人关注的物理特性。其中，最具前景的电介质GeO呈现出负泊松比效应，κ值为99，并与MoSe₂和HfSe₂形成I型异质结构，带隙偏移约为1 eV。我们的研究为设计非层状二维氧化物开辟了道路，为研究超薄氧化物中的丰富物理现象及其在未来信息技术中的潜在应用提供了一个平台。
