Wang Xiaomeng, Wang Yong, Wang Junjie, Pan Shuning, Lu Qing, Wang Hui-Tian, Xing Dingyu, Sun Jian
National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, People's Republic of China.
School of Physics and Electronic-Electrical Engineering, Ningxia University, Yinchuan, 750021, People's Republic of China.
Phys Rev Lett. 2022 Dec 9;129(24):246403. doi: 10.1103/PhysRevLett.129.246403.
Superconducting and superionic behaviors have physically intriguing dynamic properties of electrons and ions, respectively, both of which are conceptually important and have great potential for practical applications. Whether these two phenomena can appear in the same system is an interesting and important question. Here, using crystal structure predictions and first-principle calculations combined with machine learning, we identify several stable Li-Al compounds with electride behavior under high pressure, and we find that the electronic density of states of some of the compounds has characteristics of the two-dimensional electron gas. Among them, we estimate that Li_{6}Al at 150 GPa has a superconducting transition temperature of around 29 K and enters a superionic state at a high temperature and wide pressure range. The diffusion in Li_{6}Al is found to be affected by an electride and attributed to the atomic collective motion. Our results indicate that alkali metal alloys can be effective platforms to study the abundant physical properties and their manipulation with pressure and temperature.
超导行为和超离子行为分别具有电子和离子在物理上引人入胜的动态特性，这两者在概念上都很重要，并且在实际应用中具有巨大潜力。这两种现象是否能出现在同一系统中是一个有趣且重要的问题。在此，通过结合晶体结构预测、第一性原理计算以及机器学习，我们识别出了几种在高压下具有电子化合物行为的稳定锂 - 铝化合物，并且发现其中一些化合物的电子态密度具有二维电子气的特征。其中，我们估计在150吉帕压力下的Li₆Al具有约29开尔文的超导转变温度，并且在高温和宽压力范围内进入超离子态。我们发现Li₆Al中的扩散受电子化合物影响，并归因于原子集体运动。我们的结果表明，碱金属合金可以成为研究丰富物理性质以及通过压力和温度对其进行调控的有效平台。
