Prediction of superconducting ternary hydride MgGeH6: from divergent high-pressure formation routes

被引:49
作者
Ma, Yanbin [1 ]
Duan, Defang [1 ]
Shao, Ziji [1 ]
Li, Da [1 ]
Wang, Liyuan [1 ]
Yu, Hongyu [1 ]
Tian, Fubo [1 ]
Xie, Hui [1 ]
Liu, Bingbing [1 ]
Cui, Tian [1 ]
机构
[1] Jilin Univ, Coll Phys, State Key Lab Superhard Mat, Changchun 130012, Jilin, Peoples R China
基金
中国国家自然科学基金;
关键词
CRYSTAL-STRUCTURE; AB-INITIO; PSEUDOPOTENTIALS; TEMPERATURE; HYDROGEN; LITHIUM; PHASES; SYSTEM;
D O I
10.1039/c7cp05267g
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Invigorated by the high temperature superconductivity in some binary hydrogen-dominated compounds, we systematically explored high-pressure phase diagrams and superconductivity o f a ternary Mg-Ge-H system using ab initio methods. Stoichiometric MgGeH6 with high hydrogen content exhibiting Pm3 symmetry was predicted from a series o f high-pressure synthesis paths. We performed an in-depth study on three distinct formation routes to MgGeH6, i.e., Mg + Ge + 3H(2) -> MgGeH6, MgGe + 3H(2) -> MgGeH6 and MgH2 + GeH4 -> MgGeH6 at high pressures. By directly squeezing three elemental solids Mg + Ge + 3H(2), we obtained ternary MgGeH6 at 200 GPa. By adding a little bit of the MgGe alloy into hydrogen, we found that MgGeH6 can form and stabilize at about 200 GPa. More intriguingly, upon compressing MgH2 and GeH4 to 250 GPa, we also predicted the same MgGeH6. Electron structure calculations reveal that the cubic MgGeH6 is a good metal and takes on ionic character. Electron-phonon coupling calculation reveals a large lambda = 1.16 for MgGeH6 at 200 GPa. In particular, we found that ternary MgGeH6 could be a potential high temperature superconductor with a superconducting transition temperature T-c of similar to 67 K at 200 GPa.
引用
收藏
页码:27406 / 27412
页数:7
相关论文
共 60 条
[1]   TRANSITION-TEMPERATURE OF STRONG-COUPLED SUPERCONDUCTORS REANALYZED [J].
ALLEN, PB ;
DYNES, RC .
PHYSICAL REVIEW B, 1975, 12 (03) :905-922
[2]   Hydrogen dominant metallic alloys: High temperature superconductors? [J].
Ashcroft, NW .
PHYSICAL REVIEW LETTERS, 2004, 92 (18) :187002-1
[3]   Pressure-Stabilized Sodium Polyhydrides: NaHn (n > 1) [J].
Baettig, Pio ;
Zurek, Eva .
PHYSICAL REVIEW LETTERS, 2011, 106 (23)
[4]   Phonons and related crystal properties from density-functional perturbation theory [J].
Baroni, S ;
de Gironcoli, S ;
Dal Corso, A ;
Giannozzi, P .
REVIEWS OF MODERN PHYSICS, 2001, 73 (02) :515-562
[5]   What superconducts in sulfur hydrides under pressure and why [J].
Bernstein, N. ;
Hellberg, C. Stephen ;
Johannes, M. D. ;
Mazin, I. I. ;
Mehl, M. J. .
PHYSICAL REVIEW B, 2015, 91 (06)
[6]   Superconducting behavior in compressed solid SiH4 with a layered structure [J].
Chen, Xiao-Jia ;
Wang, Jiang-Long ;
Struzhkin, Viktor V. ;
Mao, Ho-kwang ;
Hemley, Russell J. ;
Lin, Hai-Qing .
PHYSICAL REVIEW LETTERS, 2008, 101 (07)
[7]   Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system [J].
Drozdov, A. P. ;
Eremets, M. I. ;
Troyan, I. A. ;
Ksenofontov, V. ;
Shylin, S. I. .
NATURE, 2015, 525 (7567) :73-+
[8]  
Duan D, 2014, SCI REP UK, V4, P6968
[9]   Structure and superconductivity of hydrides at high pressures [J].
Duan, Defang ;
Liu, Yunxian ;
Ma, Yanbin ;
Shao, Ziji ;
Liu, Bingbing ;
Cui, Tian .
NATIONAL SCIENCE REVIEW, 2017, 4 (01) :121-135
[10]   Pressure-induced decomposition of solid hydrogen sulfide [J].
Duan, Defang ;
Huang, Xiaoli ;
Tian, Fubo ;
Li, Da ;
Yu, Hongyu ;
Liu, Yunxian ;
Ma, Yanbin ;
Liu, Bingbing ;
Cui, Tian .
PHYSICAL REVIEW B, 2015, 91 (18)