Quantum and Classical Proton Diffusion in Superconducting Clathrate Hydrides.
Quantum and Classical Proton Diffusion in Superconducting Clathrate Hydrides.
复制标题
DOI：
10.1103/physrevlett.126.117002
复制
发表时间：
2021-03
影响因子：
8.6
通讯作者：
Hui Wang;Yansun Yao;Feng Peng;Hanyu Liu;R. Hemley
中科院分区：
文献类型：
--
作者：
Hui Wang;Yansun Yao;Feng Peng;Hanyu Liu;R. Hemley
笼形氢化物中近室温超导性的发现引发了对更高温度超导体的研究和对潜在物理现象的更深入理解。在这些材料的超导性的传统电子声子介导图像中，预测和观察到的高临界温度可归因于质子的低质量，但这也提出了与质子动力学如何影响超导性相关的重要问题。以笼形超氢化物Li_{2}MgH_{16}为例，通过从头路径积分模拟表明，该体系中的质子扩散非常高，扩散系数在300 K和250 GPa下达到6×10^{-6} cm^{2}/s。在这些条件下，扩散主要通过刚性 Li_{2}Mg 子晶格内的间隙空隙之间的质子转移来实现。研究结果表明质子量子扩散与氢诱导超导性共存，这对其他高温超导氢化物具有重要意义。
The discovery of near room temperature superconductivity in clathrate hydrides has ignited the search for both higher temperature superconductors and deeper understanding of the underlying physical phenomena. In a conventional electron-phonon mediated picture for the superconductivity for these materials, the high critical temperatures predicted and observed can be ascribed to the low mass of the protons, but this also poses nontrivial questions associated with how the proton dynamics affect the superconductivity. Using clathrate superhydride Li_{2}MgH_{16} as an example, we show through ab initio path integral simulations that proton diffusion in this system is remarkably high, with a diffusion coefficient, for example, reaching 6×10^{-6} cm^{2}/s at 300 K and 250 GPa. The diffusion is achieved primarily through proton transfer among interstitial voids within the otherwise rigid Li_{2}Mg sublattice at these conditions. The findings indicate the coexistence of proton quantum diffusion together with hydrogen-induced superconductivity, with implications for other very-high-temperature superconducting hydrides.