Zhang Xiaohua, Zhao Yaping, Bergara Aitor, Yang Guochun
State Key Laboratory of Metastable Materials Science and Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China.
Departamento de Física, Universidad del País Vasco-Euskal Herriko Unibertsitatea, UPV/EHU, 48080 Bilbao, Spain.
J Chem Phys. 2022 May 21;156(19):194112. doi: 10.1063/5.0092516.
Achieving a compound with interesting multiple coexisting states, such as electride, metallicity, and superconductivity, is of great interest in basic research and practical application. Pressure has become an effective way to realize high-temperature superconductivity in hydrides, whereas most electrides are semiconducting or insulating at high pressure. Here, we have applied swarm-intelligence structural search to identify a hitherto unknown C2/m LiSe electride that is superconducting at high pressure. More interestingly, LiSe is estimated to exhibit the highest T value of 16 K at 50 GPa, which is the lowest pressure among Li-based chalcogen electrides. This superconducting transition is dominated by Se-related low frequency vibration modes. The increasing electronic occupation of the Se 4d orbital and the decreasing amount of interstitial anion electrons with pressure heighten their coupling with low-frequency phonons, which is responsible for the enhancement of the T value. The finding of Li-based chalcogen superconducting electrides provides a reference for the realization of other superconducting electrides at lower pressures.
获得具有诸如电子化合物、金属性和超导性等多种有趣共存状态的化合物，在基础研究和实际应用中都具有极大的吸引力。压力已成为在氢化物中实现高温超导的有效途径，然而大多数电子化合物在高压下是半导体或绝缘体。在此，我们应用群体智能结构搜索来识别一种迄今未知的C2/m LiSe电子化合物，它在高压下具有超导性。更有趣的是，LiSe预计在50 GPa时表现出最高16 K的T值，这是锂基金属硫化物电子化合物中压力最低的。这种超导转变由与硒相关的低频振动模式主导。随着压力增加，硒4d轨道的电子占据增加以及间隙阴离子电子数量减少，增强了它们与低频声子的耦合，这导致了T值的提高。锂基金属硫化物超导电子化合物的发现为在更低压力下实现其他超导电子化合物提供了参考。
