Yuan Xiaoang, Gao Enlai
Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, People's Republic of China.
J Phys Condens Matter. 2023 Dec 7;36(10). doi: 10.1088/1361-648X/ad0d2a.
Bulk modulus and cohesive energy are two important quantities of condensed matter. From the interatomic energy landscape, we here derived a correlation between the bulk modulus () and the volumetric cohesive energy (), i.e.= 2(ln2)/9=, whereandare the strain-to-failure of interatomic bonds and the factor of proportionality, respectively. By analyzing numerous crystals from first principles calculations, it was shown that this correlation is universally applicable to various crystals including simple substances and compounds. Most interestingly, it was found thatof crystals with a similar structure are almost a constant, resulting in a linear relationship betweenand. Furthermore, we found that the value offor any compound can be determined based on the rule of mixtures, i.e.= ∑, whereandare the atomic fraction and the factor of proportionality for each element in this compound, respectively. Finally, this correlation was used to predict the bulk moduli for a vast number of crystals with knownin databases. After first principles verification of the top 50 crystals with the highest predicted bulk modulus, 25 ultraincompressible crystals with a bulk modulus greater than 400 GPa that can rival diamond (436 GPa) were discovered.
体积模量和内聚能是凝聚态物质的两个重要量。从原子间能量图景出发,我们在此推导出体积模量()与体积内聚能()之间的一种关联,即 = 2(ln2)/9 = ,其中 和 分别是原子间键的断裂应变和比例因子。通过第一性原理计算分析大量晶体表明,这种关联普遍适用于包括单质和化合物在内的各种晶体。最有趣的是,发现具有相似结构的晶体的 几乎是一个常数,从而在 和 之间产生了线性关系。此外,我们发现任何化合物的 值都可以根据混合法则来确定,即 = ∑ ,其中 和 分别是该化合物中各元素的原子分数和比例因子。最后,利用这种关联预测了数据库中大量已知 的晶体的体积模量。在对预测体积模量最高的前50种晶体进行第一性原理验证后,发现了25种体积模量大于400 GPa的超不可压缩晶体,其性能可与钻石(436 GPa)相媲美。