State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
Phys Rev Lett. 2011 Apr 8;106(14):145501. doi: 10.1103/PhysRevLett.106.145501.
Being a best known thermoelectric material and a topological insulator at ambient condition, magic bismuth telluride (Bi2Te3) under pressure transforms into several superconducting phases, whose structures remain unsolved for decades. Here, we have solved the two long-puzzling low high-pressure phases as seven- and eightfold monoclinic structures, respectively, through particle-swarm optimization technique on crystal structure prediction. Above 14.4 GPa, we experimentally discovered that Bi2Te3 unexpectedly develops into a Bi-Te substitutional alloy by adopting a body-centered cubic disordered structure stable at least up to 52.1 GPa. The continuously monoclinic distortion leads to the ultimate formation of the Bi-Te alloy, which is attributed to the Bi→Te charge transfer under pressure. Our research provides a route to find alloys made of nonmetallic elements for a variety of applications.
作为一种广为人知的热电材料和常温下的拓扑绝缘体，加压下的神奇碲化铋（Bi2Te3）会转变成几种超导相，但这些结构几十年来仍未得到解决。在这里，我们通过晶体结构预测中的粒子群优化技术，分别将两个长期困扰的高低压相解析为七重和八重单斜结构。在 14.4 GPa 以上，我们通过实验发现，Bi2Te3 出人意料地通过体心立方无序结构转变成 Bi-Te 取代型合金，该结构至少在 52.1 GPa 下稳定。持续的单斜畸变最终导致了 Bi-Te 合金的形成，这归因于加压下的 Bi→Te 电荷转移。我们的研究为寻找由非金属元素组成的合金提供了一种途径，可应用于各种领域。
