The six-membered ring (SMR) is a common structure unit for numerous material systems. These materials include, but are not limited to, the typical two-dimensional materials such as graphene, h-BN, and transition metal dichalcogenides, as well as three-dimensional materials such as beryllium, magnesium, MgB₂ and Bi₂Se₃. Although many of these materials have already become ‘stars’ in materials science and condensed-matter physics, little attention has been paid to the roles of the SMR unit across a wide range of compositions and structures. In this article, we systematically analyze these materials with respect to their very basic SMR structural unit, which has been found to play a deterministic role in the occurrence of many intriguing properties and phenomena, such as Dirac electronic and phononic spectra, superconductivity and topology. As a result, we have defined this group of materials as SMR inorganic materials, opening up a new perspective on materials research and development. With their unique properties, SMR materials deserve wide attention and in-depth investigation from materials design, new physical discoveries to target-wizard applications. It is expected that SMR materials will find niche applications in next-generation information technology, renewable energy, space, etc.

中文翻译：

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六元环无机材料：定义与展望

六元环（SMR）是众多材料系统的常见结构单元。这些材料包括但不限于石墨烯、h -BN、过渡金属二硫属化物等典型的二维材料，以及铍、镁、MgB ₂、Bi ₂ Se ₃等三维材料。尽管其中许多材料已经成为材料科学和凝聚态物理学中的“明星”，但人们很少关注 SMR 单元在各种成分和结构中的作用。在本文中，我们系统地分析了这些材料的基本 SMR 结构单元，这些结构单元被发现在许多有趣的性质和现象的发生中发挥着决定性的作用，例如狄拉克电子和声子谱、超导性和拓扑。由此，我们将这组材料定义为SMR无机材料，开辟了材料研发的新视角。凭借其独特的性能，SMR材料值得从材料设计、新物理发现到目标向导应用的广泛关注和深入研究。预计SMR材料将在下一代信息技术、可再生能源、太空等领域找到利基应用。