Superconductivity in Layered van der Waals Hydrogenated Germanene at High Pressure.
Superconductivity in Layered van der Waals Hydrogenated Germanene at High Pressure.
复制标题
DOI：
10.1021/jacs.2c05683
复制
发表时间：
2021-05
影响因子：
15
通讯作者：
Yilian Xi;Xiaolin Jing;Zhongfei Xu;Nana Liu;Yani Liu;Miao‐Ling Lin;Ming Yang;Ying Sun;
中科院分区：
文献类型：
--
作者：
Yilian Xi;Xiaolin Jing;Zhongfei Xu;Nana Liu;Yani Liu;Miao‐Ling Lin;Ming Yang;Ying Sun;
二维（2D）材料中超导性的出现吸引了巨大的研究努力，因为意外和迷人的超导现象背后的起源和机制仍然不清楚。特别是，超导电性可以生存在二维系统中，即使削弱无序和破坏空间反演对称性。在这里，二维货车德瓦耳斯（vdW）氢化锗烯（GeH）的结构和超导转变下的压缩和减压过程中观察。GeH在8.39GPa下发生超导转变，临界温度为5.41K。在16.80 GPa下发生晶体到非晶的转变，而超导性仍然存在。在减压过程中，观察到Tc异常增加至6.11 K，而GeH保持在2D非晶相。结合原位高压同步X射线衍射、原位高压拉曼光谱、透射电子显微镜和密度泛函理论模拟的研究表明，二维vdW GeH的超导电性归因于费米能级的态密度增加以及高压下非晶相的电子-声子耦合效应增强. GeH从二维晶态到二维非晶态的独特压致相变为研究非晶态氢化物超导电性机制提供了一个很好的平台。
The emergence of superconductivity in two-dimensional (2D) materials has attracted tremendous research efforts because the origins and mechanisms behind the unexpected and fascinating superconducting phenomena remain unclear. In particular, the superconductivity can survive in 2D systems even with weakened disorder and broken spatial inversion symmetry. Here, structural and superconducting transitions of 2D van der Waals (vdW) hydrogenated germanene (GeH) are observed under compression and decompression processes. GeH possesses a superconducting transition with a critical temperature (Tc) of 5.41 K at 8.39 GPa. A crystalline to amorphous transition occurs at 16.80 GPa, while superconductivity remains. An abnormal increase of Tc up to 6.11 K was observed during the decompression process, while the GeH remained in the 2D amorphous phase. A combination study of in situ high-pressure synchrotron X-ray diffraction, in situ high-pressure Raman spectroscopy, transition electron microscopy, and density functional theory simulations suggests that the superconductivity in 2D vdW GeH is attributed to the increased density of states at the Fermi level as well as the enhanced electron-phonon coupling effect under high pressure even in the form of an amorphous phase. The unique pressure-induced phase transition of GeH from 2D crystalline to 2D amorphous metal hydride provides a promising platform to study the mechanisms of amorphous hydride superconductivity.