Structural and Superconducting Properties of Tungsten Hydrides Under High Pressure

Frontiers in Physics

Zhang, Jing¹  Sun, Yu¹  Lin, Jianyan¹  Zheng, Shuang¹  Yang, Guochun¹  Zhang, Shoutao¹  Bergara, Aitor² 

[1] Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, China;Departmento de Fís Vasco, UPV/EHU, Spain;sica de la Materia Condensada, Universidad del Paí

关键词: Tungsten hydride;    Superconductivity;    High preaaure;    Structure predication;    Density funcational theory;   

DOI  :  10.3389/fphy.2018.00101

学科分类：物理（综合）

来源: Frontiers

【 摘 要 】

Unveiling the relation between crystal structure and superconductivity of hydrides becomes a fascinating research area in chemistry and condensed-mater physics. Although much efforts have been made to study chemical reaction between tungsten and hydrogen, the crystal structures, superconductivity, and phase diagram of tungsten hydrides under high pressure have not been fully explored and built thus far. In this work, we carried out extensive structural search on W-H binary compounds through first-principles swarm-intelligence structural search calculations. Besides reproducing the known W-H compounds, a new stoichiometry WH5 with P6mm symmetry becomes stable above 230.2 GPa. Intriguingly, P6mm WH5 shows a critical temperature (Tc) value of 60.8 K, which is much higher than 31.6 K in WH6. This finding is different from the knowledge of compounds with higher H content exhibiting higher Tc, which might be attributed to the appearance of unique H network and tetrahedron H units in WH5. Electronic property and superconductivity of the other tungsten hydrides are also investigated. The built pressure-composition phase diagram provides some useful information for experimental synthesis.

【 授权许可】

CC BY