Hydrogen sulfide at high pressure: Change in stoichiometry

Goncharov, Alexander F.; Lobanov, Sergey S.; Kruglov, Ivan A.; Zhao, Xinyuan; Chen, Xiao‐Jia; Oganov, Artem R.; Konôpková, Zuzana; Prakapenka, Vitali B.

doi:10.1103/physrevb.93.174105

Cited by 97 publications

(125 citation statements)

References 37 publications

Supporting

Mentioning

114

Contrasting

Order By: Relevance

“…In addition, the multiphase nature of the studied samples (Goncharov et al, 2016) also represents a serious complication. Recently, advance spectroscopy has been employed to monitor how the structure evolves with pressure (Goncharov et al, 2017).…”

mentioning

confidence: 99%

Colloquium : High pressure and road to room temperature superconductivity

Gor’kov¹,

Kresin²

2018

Rev. Mod. Phys.

128

View full text Add to dashboard Cite

High pressure serves as a path finding tool towards novel structures, including those with very high Tc. The superconductivity in sulfur hydrides with record value of Tc =203 K (!) is caused by the phonon mechanism. However, the picture differs from the conventional one in important ways. The phonon spectrum in sulfur hydride is both broad and has a complex structure. High value of T c is mainly due to strong coupling to the high-frequency optical modes, although the acoustic phonons also make a noticeable contribution. New approach is described; it generalizes the standard treatment of the phonon mechanism and makes it possible to obtain an analytical expression for Tc . It turns out that, unlike in the conventional case, the value of the isotope coefficient varies with the pressure and reflects the impact of the optical modes. The phase diagram, that is the pressure dependence of Tc, is rather peculiar. A crucial feature is that increasing pressure results in a series of structural transitions, including the one, which yields the superconducting phase with the record Tc . In a narrow region near P≈150 GPa the critical temperature rises sharply from Tc ≈120K to Tc ≈200K. The sharp structural transition, which produces the high Tc phase, is a first-order phase transition caused by interaction between the order parameter and lattice deformations. A remarkable feature of the electronic spectrum in the high Tc phase is the appearance of small pockets at the Fermi level. Their presence leads to a two-gap spectrum, which 2 can, in principle, be observed, with the future use of tunneling spectroscopy. This feature leads to non-monotonic and strongly asymmetric pressure dependence of Tc. Other hydrides can be expected to display even higher values of Tc, up to room temperature. The fundamental challenge lays in creation a structure capable of displaying high Tc at ambient pressure.

show abstract

mentioning

confidence: 99%

Colloquium : High pressure and road to room temperature superconductivity

Gor’kov¹,

Kresin²

2018

Rev. Mod. Phys.

128

View full text Add to dashboard Cite

show abstract

“…Theoretical studies, which have shown that the superconductivity observed in Ref. [38] arises primarily from an H 3 S phase [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] whose structure has been recently confirmed experimentally [56], will not be described within this short review. We will, however, discuss the results of first principles calculations carried out for the hydrides of phosphorus [57][58][59].…”

Section: Introductionmentioning

confidence: 99%

Superconductivity in Hydrides Doped with Main Group Elements Under Pressure

Shamp¹,

Zurek²

2017

Novel Superconducting Materials

View full text Add to dashboard Cite

A priori crystal structure prediction techniques have been used to explore the phase diagrams of hydrides of main group elements under pressure. A number of novel phases with the chemical formulas MHn, n > 1 and M = Li, Na, K, Rb, Cs; MHn, n > 2 and M= Mg, Ca, Sr, Ba; HnI with n > 1 and PH, PH 2 , PH 3 have been predicted to be stable at pressures achievable in diamond anvil cells. The hydrogenic lattices within these phases display a number of structural motifs including H δ− 2 , H − , H − 3 , as well as one-dimensional and three-dimensional extended structures. A wide range of superconducting critical temperatures, Tcs, are predicted for these hydrides. The mechanism of metallization and the propensity for superconductivity are dependent upon the structural motifs present in these phases, and in particular on their hydrogenic sublattices. Phases that are thermodynamically unstable, but dynamically stable, are accessible experimentally. The observed trends provide insight on how to design hydrides that are superconducting at high temperatures.

show abstract

“…4(c)). The various experimental patterns reported up to now [2,30,31] could therefore be generally involved by the Magnéli phases. Small-angle diffraction peaks due to the long-range structural modulation are commonly predicted to be formed (left panels).…”

Section: Introductionmentioning

confidence: 99%

“…Phases with various structures and compositions have been proposed with the first-principles structure-search methods, some of which have been suggested as the intermediate products [8,16,30,31,33]. Consistent explanation of the experimental scheme dependence of Tc within the conventional superconducting theory has been nevertheless unprecedented.…”

Section: Introductionmentioning

confidence: 99%

“…However, the reaction and kinetic route(s) of the phase transformation to the high-Tc H 3 S phase has been elusive: The efficient experimental protocol to realize the highTc phases is still to be established as significant dependence on the experimental compression and annealing procedures has been reported [1,2,[30][31][32]. Phases with various structures and compositions have been proposed with the first-principles structure-search methods, some of which have been suggested as the intermediate products [8,16,30,31,33].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Emergent Magnéli-type crystal phases and their mixture in pressurized sulfur hydride

Akashi¹,

Sano²,

Arita³

et al. 2017

Novel Superconducting Materials

View full text Add to dashboard Cite

Abstract:The pressure-induced superconductivity in sulfur hydride has recently received tremendous amount of interest for its record-breaking transition temperature (Tc) of 203 K. We extensively discuss an infinite sequence of metastable structures of sulfur hydride under high pressure which has been recently proposed theoretically [R. Akashi et al., Phys. Rev. Lett. 117, 075503 (2016)]. The newly found structures are understood as the stacked layers of H 2 S and H 3 S, showing close similarity to the Magnéli phases formed in transition-metal oxides. The possible emergence of the "HxS Magnéli" phases are discussed as intermediate metastable phases in the formation of the high-Tc H 3 S phase. Superconducting transition temperatures and the Xray diffraction patterns are simulated with the first-principles calculations. It is demonstrated that the HxS Magnéli phases could serve as the silver bullet to explain the complicated dependences of the observed Tcs and diffraction patterns on the experimental protocol.

show abstract

Hydrogen sulfide at high pressure: Change in stoichiometry

Abstract: Hydrogen-sulfide (H 2 S) was studied by x-ray synchrotron diffraction (XRD) and

Cited by 97 publications

References 37 publications

Colloquium : High pressure and road to room temperature superconductivity

Colloquium : High pressure and road to room temperature superconductivity

Superconductivity in Hydrides Doped with Main Group Elements Under Pressure

Emergent Magnéli-type crystal phases and their mixture in pressurized sulfur hydride

Contact Info

Product

Resources

About