典型非金属元素氢化物高压下组份的演变研究

As H2S and PH3 were reported to become superconducting at high pressures with a record breaking Tc, hydrides of non-metallic elements' have attracted a great attentions and became the focus of high pressure researches. Especially, the transitions of their stoichiometries at high pressure are crucial in understanding their superconducting mechanism. In this proposal, we propose to use diamond anvil cells coupling with Raman, IR, VIS-UV, NMR, and XRD techniques to investigate stoichiometry changes of these materials under high pressures. Their phase diagrams will be concluded and used to predict the possibility of superconductivity under high pressures. The stoichiometry of each compound will provide crucial information in understanding the superconducting mechanism. This proposal is based on our recent primary results on H2S and PH3, which could be applied into other compounds in the same groups. The results of the proposal will make a great contribution in this field.

最近对H2S和PH3在超高压条件下超导电性的相继报道，使非金属元素氢化物的高压实验和理论研究成了前沿课题和科研热点。特别是，它们在高压下的组份演变规律成了理解其超导电机制的不可或缺的基本信息，是新近高压研究的焦点。本项目将利用金刚石对顶砧高压技术，结合拉曼光谱、红外吸收光谱、紫外-可见吸收光谱、固体核磁共振和同步辐射X射线衍射等原位测量技术，对典型非金属元素氢化高压下组份的演变进行系统研究，确定各化合物在高压下组份的相图，总结它们的演变规律。进一步结合理论计算，探索各组份超导性的可能性以及超导机制。本项目依据申请者最新的实验结果所提出，聚焦于非金属元素氢化合物的组份演化研究，其结果将对富氢化合物的超导电机制提供重要依据。

氢化物相继创造了超导转变温度的最高记录,如何明晰氢化物高压相的组分和结构演变成为确认其超导电性起源的关键科学问题。在对该项目进行实施的四年里，我们利用多种高压原位测试手段，系统地研究了Si-H、P-H、As-H、H-Te及C-H等在高压下的组分演化和物性，厘清了它们在高压下的组分演化规律，为寻找新型超导氢化物提供了重要实验数据。主要研究成果包括：1. 发现了PH3在高压下的压致聚合，获得P2H4、P4H6两种新型P-H化合物，进一步确定了P4H6为超导组分；2. 发现了AsH3、SiH4在高压下的聚合行为，为人们重新认识As-H和Si-H体系，寻找新型超导氢化物理提供了重要实验依据；3. 合成出了一系列非常规摩尔比的高压氢化物以及氢化物和氢组成的范德瓦尔斯晶体，并确认了它们在高压下的演化规律，丰富了氢化物类型。. 项目执行期间发表相关SCI论文18篇，包括National Science Review和Materials Today Physics等。其中8篇第一标注了本项目，8篇为第二标注、2篇为第四标注。另外有3-5篇论文在整理和投稿过程中。. 培养博士研究生3名，硕士研究生2名，2名博士后出站。