Xu Ming, Duan Defang, Du Mingyang, Zhao Wendi, An Decheng, Song Hao, Cui Tian
Institute of High Pressure Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China.
State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
Phys Chem Chem Phys. 2023 Dec 6;25(47):32534-32540. doi: 10.1039/d3cp03952h.
The search for high-temperature superconductors in hydrides under high pressure has always been a research hotspot. Hydrogen-based superconductors offer an avenue to achieve the long-sought goal of superconductivity at room temperature. Here we systematically explored the high-pressure phase diagram, electronic properties, lattice dynamics and superconductivity of the ternary Ca-Al-H system using methods. At 80 GPa, CaAlH transforms from to 2/ phase. Both of -CaAlH and -CaAlH are semiconductors. At 200 GPa, 4/-CaAlH and a metastable compound -CaAlH were found. Furthermore, 4/-CaAlH shows obvious softening of the high frequency vibration modes, which improves the strength of electron-phonon coupling. Therefore, a superconducting transition temperature of 71 K is generated in 4/-CaAlH at 50 GPa. In addition, the thermodynamic metastable -CaAlH exhibits a superconducting transition temperature of 118 K at 250 GPa. These results are very useful for the experimental searching of new high- superconductors in ternary hydrides. Our work may provide an opportunity to search for high superconductors at lower pressure.
在高压下寻找氢化物中的高温超导体一直是一个研究热点。基于氢的超导体为实现长期以来在室温下超导的目标提供了一条途径。在这里，我们使用多种方法系统地探索了三元Ca-Al-H体系的高压相图、电子性质、晶格动力学和超导性。在80吉帕斯卡时，CaAlH从 转变为2/相。-CaAlH和-CaAlH均为半导体。在200吉帕斯卡时，发现了4/-CaAlH和一种亚稳化合物-CaAlH。此外，4/-CaAlH的高频振动模式明显软化，这增强了电子-声子耦合强度。因此，在50吉帕斯卡时，4/-CaAlH中产生了71开尔文的超导转变温度。此外，热力学亚稳的-CaAlH在250吉帕斯卡时表现出118开尔文的超导转变温度。这些结果对于在三元氢化物中实验寻找新型高温超导体非常有用。我们的工作可能为在较低压力下寻找高温超导体提供机会。
