Stability and superconductivity of lanthanum and yttrium decahydrides

Shipley, Alice M.; Hutcheon, Michael; Johnson, M. D.; Needs, R. J.; Pickard, Chris J.

doi:10.1103/physrevb.101.224511

Cited by 28 publications

(29 citation statements)

References 54 publications

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“…[22] The CO/Cu(100) 2 × 2 supercell captures significant friction with small broadening windows, though the dependence with respect to k-grid size appears to be less stable (panel b). The instability at small smearing widths is similarly reported by Shipley et al [67] (albeit for polyhydrides) when accounting for q > 0 excitations. The agreement between different k-grid sizes does improve at larger values of σ, however, excessively high values of σ will incur errors and formally are not justified within first-order perturbation theory.…”

Section: Convergence Of Electronic Friction Tensor and Vibrational Li...supporting

confidence: 76%

Ab initio calculation of electron-phonon linewidths and molecular dynamics with electronic friction at metal surfaces with numeric atom-centered orbitals

Box¹,

Stark²,

Maurer³

2021

Preprint

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Molecular motion at metallic surfaces is affected by nonadiabatic effects and electron-phonon coupling. The ensuing energy dissipation and dynamical steering effects are not captured by classical molecular dynamics simulations, but can be described with the molecular dynamics with electronic friction method and linear response calculations based on density functional theory. Herein, we present an implementation of electron-phonon response based on an all-electron numeric atomic orbital description in the electronic structure code FHI-aims. After providing details of the underlying approximations and numerical considerations, we present significant scalability and performance improvements of the new code compared to a previous implementation [Phys. Rev. B 94, 115432 (2016)]. We compare convergence behaviour and results of our simulations for exemplary systems such as CO on Cu(100), H 2 adsorption on Cu(111), and CO on Ru(0001) against existing plane wave implementations. We find that our all-electron calculations exhibit faster and more monotonic convergence behaviour than conventional plane-wave-based electron-phonon calculations. Our findings suggest that many electron-phonon linewidth calculations in literature may be underconverged. Finally, we showcase the capabilities of the new code by studying the contribution of interband and intraband excitations to vibrational linewidth broadening of aperiodic motion in previously unfeasibly large periodic surface models.

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Section: Convergence Of Electronic Friction Tensor and Vibrational Li...supporting

confidence: 76%

Ab initio calculation of electron-phonon linewidths and molecular dynamics with electronic friction at metal surfaces with numeric atom-centered orbitals

Box¹,

Stark²,

Maurer³

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…[17] A second class of compounds with high T c s, which were computationally predicted [18,19] prior to their synthesis, are metal superhydrides including LaH 10 (T c = 250-260 K near 200 GPa), [20,21] YH 9 (T c = 262 K at 182 GPa) [22] and YH 6 (T c = 224 K at 166 GPa). [23] These findings have inspired theoretical investigations of the superconducting mechanism, pressure dependence of T c , and anharmonic effects in LaH 10 as well as the isotypic YH 10 phase, [24][25][26][27][28] and the relationship between electronic structure and superconductivity in rare earth (RE) polyhydrides, REH n with n ¼ 8; 9; 10. [29] Another crystalline lattice that is predicted to be ubiquitous among the highpressure alkaline and RE metal hydrides is an I4=mmm symmetry MH 4 phase containing hydridic and quasi-molecular hydrogen atoms with a formula that can be written as M…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure and Superconductivity of Compressed Metal Tetrahydrides

Zurek

2021

Chemistry A European J

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Tetrahydrides crystallizing in the ThCr 2 Si 2 structure type have been predicted to become stable for a plethora of metals under pressure, and some have recently been synthesized. Through detailed first-principles investigations we show that the metal atoms within these I4=mmm symmetry MH 4 compounds may be divalent, trivalent or tetravalent. The valence of the metal atom and its radius govern the bonding and electronic structure of these phases, and their evolution under pressure. The factors important for enhancing superconductivity include a large number of hydrogenic states at the Fermi level, and the presence of quasi-molecular H dÀ 2 units whose bonds have been stretchedand weakened (but not broken) via electron transfer from the electropositive metal, and via a Kubas-like interaction with the metal. Analysis of the microscopic mechanism of superconductivity in MgH 4 , ScH 4 and ZrH 4 reveals that phonon modes involving a coupled libration and stretch of the H dÀ 2 units leading to the formation of more complex hydrogenic motifs are important contributors towards the electron phonon coupling mechanism. In the divalent hydride MgH 4 , modes associated with motions of the hydridic hydrogen atoms are also key contributors, and soften substantially at lower pressures.

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“…Nowadays, superconductivity is one of the most charming in physical properties. Many materials were predicted to be a superconducting transition temperature (T c ), such as SH 3 [22][23][24][25], LaH 10 [26][27][28], YH 10 [28][29][30], CeH 10 [17, 31]. It is worth note that hydrogen (H) is a role important for promoting a T c .…”

Section: Introductionmentioning

confidence: 99%

Superconductivity in Materials under Extreme Conditions: An ab-initio Prediction from Density Functional Theory

Bovornratanaraks¹,

Tsuppayakorn‐aek²

2022

Density Functional Theory - Recent Advances, New Perspectives and Applications

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The relation between thermodynamically stable and electronic structure preparation is one of the fundamental questions in physics, geophysics and chemistry. Since the discovery of the novel structure, this has remained as one of the main questions regarding the very foundation of elemental metals. Needless to say this has also bearings on extreme conditions physics, where again the relation between structure and performance is of direct interest. Crystal structures have been mainly at ambient conditions, i.e. at room temperature and ambient pressure. Nevertheless it was realized early that there is also a fundamental relation between volume and structure, and that this dependence could be most fruitfully studied by means of high pressure experimental techniques. From a theoretical point of view this is an ideal type of experiment, since only the volume is changed, which is a very clean variation of the external conditions. Therefore, at least in principle, the theoretical approach remains the same irrespective of the high pressure loading of the experimental sample. Theoretical modeling is needed to explain the measured data on the pressure volume relationships in crystal structures. Among those physical properties manifested itself under high pressure, superconductivity has emerged as a prominent property affected by pressure. Several candidate structure of materials are explored by ab initio random structure searching (AIRSS). This has been carried out in combination with density functional theory (DFT). The remarkable solution of AIRSS is possible to expect a superconductivity under high pressure. This chapter provide a systematically review of the structural prediction and superconductivity in elemental metals, i.e. lithium, strontium, scandium, arsenic.

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Stability and superconductivity of lanthanum and yttrium decahydrides

Cited by 28 publications

References 54 publications

Ab initio calculation of electron-phonon linewidths and molecular dynamics with electronic friction at metal surfaces with numeric atom-centered orbitals

Ab initio calculation of electron-phonon linewidths and molecular dynamics with electronic friction at metal surfaces with numeric atom-centered orbitals

Electronic Structure and Superconductivity of Compressed Metal Tetrahydrides

Superconductivity in Materials under Extreme Conditions: An ab-initio Prediction from Density Functional Theory

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