Synthesis of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Ni</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>at high temperatures and pressures

Binns, Jack; Donnelly, Mark I.; Wang, Mengnan; Hermann, Andreas; Gregoryanz, Eugene; Dalladay‐Simpson, Philip; Howie, Ross T.

doi:10.1103/physrevb.98.140101

Cited by 15 publications

(14 citation statements)

References 43 publications

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“…studied B 10 H 14 [402] and its transformation under pressure. Other systems studied for their potential transformation to a metallic substance include: He-H [403], Li-H [404], Na-H [405], H-O [406,407], AlH 3 [408], Fe-H [409,410,411,412,413], Co-H [414], Ni-H [415,416], Si-H [417,418,36]. Cu-H [419], SeH 3 [420], Nb-H [421], Rh-H [422], I-H [423], Ta-H [424], Ce-H [425], Eu-H [426], La-Ni-H [427] and other rare earth trihydrides under high pressure [428].…”

Section: Non-superconducting Hydridesmentioning

confidence: 99%

A perspective on conventional high-temperature superconductors at high pressure: Methods and materials

et al. 2020

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Two hydrogen-rich materials: H 3 S and LaH 10 , synthesized at megabar pressures have revolutionized the field of superconductivity by providing a first glimpse into the solution for the hundred-year-old problem of room-temperature superconductivity. The mechanism governing these exceptional superconductors is the conventional electron-phonon coupling. Here, we describe recent advances in experimental techniques, superconductivity theory and first-principles computational methods, which made this discovery possible. The aim of this work is to provide an up-to-date compendium of the available results on superconducting hydrides and explain the synergy of different methodologies that led to the extraordinary discoveries in the field. Furthermore, in an attempt to evidence empirical rules governing superconductivity in binary hydrides under pressure, we discuss general trends in electronic structure and chemical bonding. The last part of the Review introduces possible strategies to optimize pressure and transition temperatures in conventional superconducting materials. Directions for future research in areas of theory, computational methods and high-pressure experiments are proposed, in order to advance our understanding of superconductivity.

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Section: Non-superconducting Hydridesmentioning

confidence: 99%

A perspective on conventional high-temperature superconductors at high pressure: Methods and materials

et al. 2020

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“…[27] This discovery had been followed by an investigation of (HI)(H 2 ) 13 obtained as a small impurity in HI(H 2 ) after the laser heating of the H 2 + I 2 mixture above 25 GPa. [28] A significant difference of strontium hydrides from xenon and iodine (HI) polyhydrides is a strong charge transfer and polarization of the SrH bonds. Indeed, Bader charge analysis performed in accordance with our previous experience [29,30] (Table S9, Supporting Information) shows that the Sr atoms are a source of electrons for hydrogen.…”

Section: Structure Prediction and Synthesis Of Srh 22mentioning

confidence: 99%

Sr‐Doped Superionic Hydrogen Glass: Synthesis and Properties of SrH₂₂

et al. 2022

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experimental metallization limit moving step by step from 150 [4] to 430-500 GPa. [1,5] A consistent increase in pressure leads to a series of phase transitions in solid hydrogen (phases Ι-V [1,5] ), gradual quenching of the Raman signals, and darkening of the sample down to a complete loss of transparency. Despite a significant progress in achieving ultrahigh pressures in the last five years, detecting superconductivity of metallic hydrogen remains an unsolved problem. Studies of the electrical conductivity at pressures above 400 GPa remain very challenging.In 2004, N. Ashcroft suggested that the precompression effects caused by chemical bonding to other atoms may help to convert hydrogen to a metallic state. Fifteen years later, this idea was confirmed in the synthesis of many metallic and superconducting hydrides such as H 3 S, [6,7] LaH 10 , [8,9] YH 6 , [10,11] YH 9 , [11,12] ThH 10 , [13] CeH 9 , [14] PrH 9 , [15] NdH 9 , [16] and so forth. It is believed now that the superconducting properties of these compounds are due to the presence of a sublattice of metallic hydrogen, which is formed in pure hydrogen only at pressures of 500-700 GPa.There must be an intermediate link between these two forms of hydrogen, metallic and superconducting, and a molecular Recently, several research groups announced reaching the point of metallization of hydrogen above 400 GPa. Despite notable progress, detecting superconductivity in compressed hydrogen remains an unsolved problem. Following the mainstream of extensive investigations of compressed metal polyhydrides, here small doping of molecular hydrogen by strontium is demonstrated to lead to a dramatic reduction in the metallization pressure to ≈200 GPa. Studying the high-pressure chemistry of the Sr-H system, the formation of several new phases is observed: C2/m-Sr 3 H 13 , pseudocubic SrH 6 , SrH 9 with cubic F m 43 -Sr sublattice, and pseudo tetragonal superionic P1-SrH 22 , the metal hydride with the highest hydrogen content (96 at%) discovered so far. High diffusion coefficients of hydrogen in the latter phase D H = 0.2-2.1 × 10 −9 m 2 s −1 indicate an amorphous state of the H-sublattice, whereas the strontium sublattice remains solid. Unlike Ca and Y, strontium forms molecular semiconducting polyhydrides, whereas calcium and yttrium polyhydrides are high-T C superconductors with an atomic H sublattice. The discovered SrH 22 , a kind of hydrogen sponge, opens a new class of materials with ultrahigh content of hydrogen.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202200924.

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“…12 Through a combination of high pressure and/or high temperature, TMH with more unusual stochiometries become energetically competitive. [13][14][15][16][17][18][19][20][21][22] Iron exhibits several polyhydride species, of which FeH 5 (I4/mmm), synthesised at 120 GPa and temperatures >1500 K, is the most hydrogen-rich and possesses a unique layered structure. 23 Potential superconductivity in FeH 5 has been a subject of debate, with two theoretical works predicting remarkably high T c values ranging between 46 -51 K, and conversely, another computational study finding no superconductivity.…”

Section: Take Down Policymentioning

confidence: 99%

“…We also do not observe a transition on compression to tetragonal (I4/mmm) CoH 2 , which was predicted to become energetically favourable above 42 GPa. 27 The laser heating of metals in a high-pressure hydrogen environment has been a successful synthetic tool in yielding hydrogen-rich metal hydrides, 3,17,30,31 and was utilised here to explore the synthesis of cobalt polyhydride species. Samples of CoH/CoH 2 and H 2 were compressed to pressures of 75 GPa and 88 GPa, and held here for 24 and 12 hours respectively, observing no time induced transformation.…”

Section: Graphical Toc Entrymentioning

confidence: 99%

Synthesis of Superconducting Cobalt Trihydride

Peña-Álvarez

Kelsall

et al. 2020

J. Phys. Chem. Lett.

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The Co-H system has been investigated through high-pressure high-temperature x-ray diffraction experiments combined with first principles calculations. On compression of elemental cobalt in a hydrogen medium, we observe fcc cobalt hydride (CoH) and cobalt dihydride (CoH 2 ) at 33 GPa. Laser heating CoH 2 in a hydrogen matrix at 75 GPa to temperatures in excess of ∼ 800 K, produces cobalt trihydride (CoH 3 ) which adopts a primitive structure. Density functional theory calculations support the stability of CoH 3 . This phase is predicted to be thermodynamically stable at pressures above 18 GPa and to be a superconductor below 23 K as critical temperature, T c . Theory

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Synthesis ofNi2H3at high temperatures and pressures

Cited by 15 publications

References 43 publications

A perspective on conventional high-temperature superconductors at high pressure: Methods and materials

A perspective on conventional high-temperature superconductors at high pressure: Methods and materials

Sr‐Doped Superionic Hydrogen Glass: Synthesis and Properties of SrH₂₂

Synthesis of Superconducting Cobalt Trihydride

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Synthesis ofNi2H3at high temperatures and pressures

Cited by 15 publications

References 43 publications

A perspective on conventional high-temperature superconductors at high pressure: Methods and materials

A perspective on conventional high-temperature superconductors at high pressure: Methods and materials

Sr‐Doped Superionic Hydrogen Glass: Synthesis and Properties of SrH22

Synthesis of Superconducting Cobalt Trihydride

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Sr‐Doped Superionic Hydrogen Glass: Synthesis and Properties of SrH₂₂