Publisher’s Note: High Pressure Stabilization and Emergent Forms of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>PbH</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>[Phys. Rev. Lett.<b>107</b>, 037002 (2011)]

Zaleski‐Ejgierd, Patryk; Hoffmann, Roald; Ashcroft, N. W.

doi:10.1103/physrevlett.107.059902

Cited by 24 publications

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“…S6 shows, 17 the closest groundstate separation between two H atoms in static Cmmm NbH 6 is 1.00Å at 400 GPa (between the two atoms parallel to x axis). In the other high-pressure NbH 6 form, C2/c, the shortest H-H separation at 400 GPa is also 1.00Å. There is again no clear pairing of H atoms in either structure.…”

Section: As a Cutoff For Identifying H-h Separations In Cmmmmentioning

confidence: 80%

“…17) indicates that the electronic DOS at the Fermi level originates, as expected, mostly from the Nb 4d orbitals. However, in the higher hydrides, given the polarity Nb δ+ H δ− , one also expects and obtains contributions to the DOS near the Fermi level from the hydrogens as well, especially for NbH 4 and NbH 6 . The hydrides studied have reasonably high electronic densities of states at the Fermi level, as one can judge through comparison with the DOS obtained in a free electron approximation (the red dot in each DOS).…”

Section: K Dynamical Stability For Different Stoichiometriesmentioning

confidence: 99%

“…By comparison the networks of hydrogens, all the hydrogens in the high-pressure structure (I m-3m) of CaH 6 form a sodalite like clathrate and the H-H separations between H-H neighbors are all 1.24Å at a much lower pressure, 150 GPa. 5 The important difference between the CaH 6 cagelike structure and our NbH 6 equivalent is that our structure is not stabilized until much higher pressures (than the 150 GPa reported for CaH 6 ). The relative compressions are 2.06 for NbH 6 at 400 GPa and 1.85 for CaH 6 at 150 GPa.…”

Section: As a Cutoff For Identifying H-h Separations In Cmmmmentioning

confidence: 99%

“…In order to make clear in electronic terms the reasons for concentrating above on H-H bonding, especially in NbH 6 , we and others have found in alkali metal, alkaline-earth metal hydrides, and also in WH n , that a way to understand the structure is to think of initial electron transfer from the electropositive element to H 2 units. With sufficient electron transfer, an H 2 2δ− will be expected to dissociate into 2H δ− , which would then enter into an extended hydridic network.…”

Section: As a Cutoff For Identifying H-h Separations In Cmmmmentioning

confidence: 99%

“…Also the quest for metallic hydrogen under pressure has also involved several theoretical groups in the examination of metal hydrides; particularly, we mention here investigations of alkali and alkaline earth hydrides, 2-5 group 14 hydrides, [6][7][8] and the tungsten hydrides, 9 some of these carried out by our own research groups. We were led to look at the niobium hydrides in particular by the following additional observation: it is well known that the transition metal Nb holds the record for the highest superconducting transition temperature T c (9.3 K) of an element at normal pressure, 10 and compounds of Nb, such as Nb 3 Ge (23 K), 11 NbC (11 K), 12 and NbN (16 K), 13 also have the highest T c values for their respective classes.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical study of the ground-state structures and properties of niobium hydrides under pressure

et al. 2013

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As part of a search for enhanced superconductivity, we explore theoretically the ground-state structures and properties of some hydrides of niobium over a range of pressures and particularly those with significant hydrogen content. A primary motivation originates with the observation that under normal conditions niobium is the element with the highest superconducting transition temperature (T c ), and moreover some of its compounds are metals again with very high T c 's. Accordingly, combinations of niobium with hydrogen, with its high dynamic energy scale, are also of considerable interest. This is reinforced further by the suggestion that close to its insulator-metal transition, hydrogen may be induced to enter the metallic state somewhat prematurely by the addition of a relatively small concentration of a suitable transition metal. Here, the methods used correctly reproduce some ground-state structures of niobium hydrides at even higher concentrations of niobium. Interestingly, the particular stoichiometries represented by NbH 4 and NbH 6 are stabilized at fairly low pressures when proton zero-point energies are included. While no paired H 2 units are found in any of the hydrides we have studied up to 400 GPa, we do find complex and interesting networks of hydrogens around the niobiums in high-pressure NbH 6 . The Nb-Nb separations in NbH n are consistently larger than those found in Nb metal at the respective pressures. The structures found in the ground states of the high hydrides, many of them metallic, suggest that the coordination number of hydrogens around each niobium atom grows approximately as 4n in NbH n (n = 1-4), and is as high as 20 in NbH 6 . NbH 4 is found to be a plausible candidate to become a superconductor at high pressure, with an estimated T c ∼ 38 K at 300 GPa.

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Section: As a Cutoff For Identifying H-h Separations In Cmmmmentioning

confidence: 80%

Section: K Dynamical Stability For Different Stoichiometriesmentioning

confidence: 99%

Section: As a Cutoff For Identifying H-h Separations In Cmmmmentioning

confidence: 99%

Section: As a Cutoff For Identifying H-h Separations In Cmmmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Theoretical study of the ground-state structures and properties of niobium hydrides under pressure

et al. 2013

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Non‐Fermi‐Liquid Behavior of Superconducting SnH₄

Troyan,

Semenok,

Ivanova

et al. 2023

Advanced Science

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The chemical interaction of Sn with H2 by X‐ray diffraction methods at pressures of 180–210 GPa is studied. A previously unknown tetrahydride SnH4 with a cubic structure (fcc) exhibiting superconducting properties below TC = 72 K is obtained; the formation of a high molecular C2/m‐SnH14 superhydride and several lower hydrides, fcc SnH2, and C2‐Sn12H18, is also detected. The temperature dependence of critical current density JC(T) in SnH4 yields the superconducting gap 2Δ(0) = 21.6 meV at 180 GPa. SnH4 has unusual behavior in strong magnetic fields: B,T‐linear dependences of magnetoresistance and the upper critical magnetic field BC2(T) ∝ (TC – T). The latter contradicts the Wertheimer–Helfand–Hohenberg model developed for conventional superconductors. Along with this, the temperature dependence of electrical resistance of fcc SnH4 in non‐superconducting state exhibits a deviation from what is expected for phonon‐mediated scattering described by the Bloch‐Grüneisen model and is beyond the framework of the Fermi liquid theory. Such anomalies occur for many superhydrides, making them much closer to cuprates than previously believed.

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Rubidium Polyhydrides Under Pressure: Emergence of the Linear H₃⁻ Species

Hooper

Zurek

2012

Chemistry A European J

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The structures of compressed rubidium polyhydrides, RbH(n) with n>1, and their evolution under pressure are studied using density functional theory calculations. These phases, which start to stabilize at only P = 2 GPa, consist of Rb(+) cations and one or more of the following species: H(-) anions, H(2) molecules, and H(3)(-) molecules. The latter motif, the simplest example of a three-center four-electron bond, is found in the most stable structures, RbH(5) and RbH(3) , which metallize above 200 GPa. At the highest pressures studied, our evolutionary searches find an RbH(6) phase which contains polymeric (H(3)(-))(∞) chains that show signs of one-dimensional liquid-like behavior.

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Publisher’s Note: High Pressure Stabilization and Emergent Forms ofPbH4[Phys. Rev. Lett.107, 037002 (2011)]

Cited by 24 publications

References 0 publications

Theoretical study of the ground-state structures and properties of niobium hydrides under pressure

Theoretical study of the ground-state structures and properties of niobium hydrides under pressure

Non‐Fermi‐Liquid Behavior of Superconducting SnH₄

Rubidium Polyhydrides Under Pressure: Emergence of the Linear H₃⁻ Species

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Publisher’s Note: High Pressure Stabilization and Emergent Forms ofPbH4[Phys. Rev. Lett.107, 037002 (2011)]

Cited by 24 publications

References 0 publications

Theoretical study of the ground-state structures and properties of niobium hydrides under pressure

Theoretical study of the ground-state structures and properties of niobium hydrides under pressure

Non‐Fermi‐Liquid Behavior of Superconducting SnH4

Rubidium Polyhydrides Under Pressure: Emergence of the Linear H3− Species

Contact Info

Product

Resources

About

Non‐Fermi‐Liquid Behavior of Superconducting SnH₄

Rubidium Polyhydrides Under Pressure: Emergence of the Linear H₃⁻ Species