High-Temperature Superconductivity in a Th-H System under Pressure Conditions.

New stable phase thorium decahydride Fm3̅ m-ThH10, a high-temperature superconductor with TC up to 241 K (-32 °C), critical field HC up to 71 T, and superconducting gap Δ0 of 52 meV at 80-100 GPa, is predicted by evolutionary algorithm USPEX. Another phase, P21/ c-ThH7, is found to be a superconductor with TC of 62 K. Analysis of the superconducting state was performed within Eliashberg formalism, and HC( T), Δ( T), and TC( P) functions with a jump in the specific heat at critical temperature were calculated. Several other new thorium hydrides were predicted to be stable under pressure, including ThH3, Th3H10, ThH4, and ThH6. Thorium (which has s2 d2 electronic configuration) forms high- TC polyhydrides similar to those formed by s2 d1 metals (Y-La-Ac). Thorium belongs to the Mg-Ca-Sc-Y-La-Ac family of elements forming high- TC superconducting hydrides.

[1]  G. Geneste,et al.  Synthesis of bulk chromium hydrides under pressure of up to 120 GPa , 2018 .

[2]  Yanli Wang,et al.  Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials , 2009 .

[3]  A. P. Drozdov,et al.  Conventional superconductivity at 190 K at high pressures , 2014, 1412.0460.

[4]  L. Pietronero,et al.  High‐temperature study of superconducting hydrogen and deuterium sulfide , 2015, 1511.05322.

[5]  Hui Wang,et al.  Compressed sodalite-like MgH6 as a potential high-temperature superconductor , 2015 .

[6]  E. Colineau,et al.  Superconductivity in transuranium elements and compounds , 2014 .

[7]  A. Oganov,et al.  Superconductivity of novel tin hydrides (SnnHm) under pressure , 2015, Scientific Reports.

[8]  C. Satterthwaite,et al.  SUPERCONDUCTIVITY OF HYDRIDES AND DEUTERIDES OF THORIUM. , 1970 .

[9]  B. Cunningham,et al.  Crystal structure and melting point of curium metal , 1964 .

[10]  A. P. Drozdov,et al.  Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system , 2015, Nature.

[11]  G. Varelogiannis.  On the limits of consistency of Eliashberg theory and the density of states of high-Tc superconductors , 1997 .

[12]  R. Hoffmann,et al.  High Hydrides of Scandium under Pressure: Potential Superconductors , 2018 .

[13]  A. Oganov,et al.  How evolutionary crystal structure prediction works--and why. , 2011, Accounts of chemical research.

[14]  Zhonglong Zhao,et al.  High pressure structures and superconductivity of AlH3(H2) predicted by first principles , 2015 .

[15]  W. Kohn,et al.  Self-Consistent Equations Including Exchange and Correlation Effects , 1965 .

[16]  E. Maksimov,et al.  REVIEWS OF TOPICAL PROBLEMS: The electron-phonon interaction and the physical properties of metals , 1997 .

[17]  N. Medvedeva,et al.  Electronic band structure of thorium hydrides: ThH2 and Th4H15 , 2007 .

[18]  P. Hohenberg,et al.  Inhomogeneous Electron Gas , 1964 .

[19]  Hafner,et al.  Ab initio molecular dynamics for liquid metals. , 1995, Physical review. B, Condensed matter.

[20]  Y. Vohra,et al.  Thorium: Phase transformations and equation of state to 300 GPa , 1992 .

[21]  A. Durajski,et al.  Superconductivity well above room temperature in compressed MgH6 , 2016 .

[22]  Yanming Ma,et al.  Superconducting high pressure phase of germane. , 2008, Physical review letters.

[23]  Roald Hoffmann,et al.  Potential high-Tc superconducting lanthanum and yttrium hydrides at high pressure , 2017, Proceedings of the National Academy of Sciences.

[24]  Fujio Izumi,et al.  VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data , 2011 .

[25]  D. Mcelroy,et al.  The electrical resistivity and specific heat of americium metal , 1978 .

[26]  B. J. Aylett.  Chemistry of the elements , 1985 .

[27]  A. Oganov,et al.  Synthesis of clathrate cerium superhydride CeH9 at 80 GPa with anomalously short H-H distance , 2018 .

[28]  G. Raynor,et al.  THE LATTICE SPACING OF THORIUM, WITH REFERENCE TO CONTAMINATION , 1959 .

[29]  Hafner,et al.  Ab initio molecular-dynamics simulation of the liquid-metal-amorphous-semiconductor transition in germanium. , 1994, Physical review. B, Condensed matter.

[30]  Qiang Zhu,et al.  New developments in evolutionary structure prediction algorithm USPEX , 2013, Comput. Phys. Commun..

[31]  J. Carbotte,et al.  Properties of boson-exchange superconductors , 1990 .

[32]  A. Oganov,et al.  Crystal structure prediction using ab initio evolutionary techniques: principles and applications. , 2006, The Journal of chemical physics.

[33]  Yanming Ma,et al.  Pressure-stabilized superconductive yttrium hydrides , 2015, Scientific Reports.

[34]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[35]  G. Kresse,et al.  From ultrasoft pseudopotentials to the projector augmented-wave method , 1999 .

[36]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[37]  Takahiro Ishikawa,et al.  Crystal Structure of the Superconducting Phase of Sulfur Hydride , 2015, Nature Physics.

[38]  Mertig,et al.  Electron-phonon coupling of the actinide metals. , 1985, Physical review. B, Condensed matter.

[39]  Artem R Oganov,et al.  Actinium Hydrides AcH10, AcH12, and AcH16 as High-Temperature Conventional Superconductors. , 2018, The journal of physical chemistry letters.

[40]  A. B. Migdal,et al.  INTERACTION BETWEEN ELECTRONS AND THE LATTICE VIBRATIONS IN A NORMAL METAL , 1958 .

[41]  Artem R. Oganov,et al.  Uranium polyhydrides at moderate pressures: Prediction, synthesis, and expected superconductivity , 2017, Science Advances.

[42]  R. Hemley,et al.  Evidence for Superconductivity above 260 K in Lanthanum Superhydride at Megabar Pressures. , 2018, Physical review letters.

[43]  D. Finnemore,et al.  Critical-Field Curves for Gapless Superconductors , 1968 .

[44]  G. M. Éliashberg,et al.  Interactions between electrons and lattice vibrations in a superconductor , 1960 .

[45]  A. Oganov,et al.  Synthesis of clathrate cerium superhydride CeH9 at 80-100 GPa with atomic hydrogen sublattice , 2018, Nature Communications.

[46]  A. Durajski,et al.  First-principles study of superconducting hydrogen sulfide at pressure up to 500 GPa , 2017, Scientific Reports.

[47]  Maria Baldini,et al.  Synthesis and Stability of Lanthanum Superhydrides. , 2018, Angewandte Chemie.

[48]  I. Tanaka,et al.  First principles phonon calculations in materials science , 2015, 1506.08498.

[49]  Da Li,et al.  Pressure-induced metallization of dense (H2S)2H2 with high-Tc superconductivity , 2014, Scientific Reports.

[50]  V. Minkov,et al.  Superconductivity at 215 K in lanthanum hydride at high pressures , 2018, 1808.07039.

[51]  Hui Wang,et al.  Superconductive sodalite-like clathrate calcium hydride at high pressures , 2012, Proceedings of the National Academy of Sciences.

[52]  Chris J. Pickard,et al.  Structure of phase III of solid hydrogen , 2007 .

[53]  Artem R. Oganov,et al.  Hydrogen sulfide at high pressure: change in stoichiometry , 2016 .

[54]  Stefano de Gironcoli,et al.  Phonons and related crystal properties from density-functional perturbation theory , 2000, cond-mat/0012092.

[55]  Kresse,et al.  Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. , 1996, Physical review. B, Condensed matter.

[56]  C. Satterthwaite,et al.  Pressure dependence of the superconducting transition temperature of Th4H15 , 1974 .

[57]  Thorium , 1943, Science.

[58]  High-pressure crystal structures and superconductivity of Stannane ( SnH 4 ) , 2010 .

[59]  Hui Wang,et al.  High-pressure crystal structures and superconductivity of Stannane (SnH4) , 2010, Proceedings of the National Academy of Sciences.

[60]  Isao Tanaka,et al.  First-principles calculations of the ferroelastic transition between rutile-type and CaCl2-type SiO2 at high pressures , 2008 .