Novel superconducting structures of BH<sub>2</sub> under high pressure

Yang, Wen‐Hua; Lu, Wen‐Cai; Li, Shandong; Xue, Xu; Zang, Qing-Jun; Ho, Kai‐Ming; Wang, Cai‐Zhuang

doi:10.1039/c9cp00310j

Cited by 20 publications

(16 citation statements)

References 50 publications

(53 reference statements)

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“…Before investigating the phase stability of ternary La-B-H compounds under pressure, we first assessed information about the La-H, B-H, and La-B binaries. The high-pressure behavior of the B-H [34][35][36] and La-H [12,13,[45][46][47] binaries has been well-studied in recent years, whereas information on the La-B system under pressure is lacking. We therefore performed structure-search calculations for La n B m (n = 1, m = 1-8; n = 2, m = 1) with system sizes containing up to 4 or 8 formula units (f.u.)…”

Section: Resultsmentioning

confidence: 99%

“…Theoretical studies indicate that adding Li and Ca to the B-H binary stabilizes phases that accommodate more atomic H atoms, leading to ternary hydrides with higher T c 's relative to those found for B-H phases [32][33][34][35][36]. Given its larger ionic radius at ambient pressure, La can accommodate more atomic H (e.g., as a superhydride) compared to Li and Ca [12].…”

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confidence: 99%

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Prediction of high- Tc superconductivity in ternary lanthanum borohydrides

et al. 2021

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The study of superconductivity in compressed hydrides is of great interest due to measurements of high critical temperatures (T c ) in the vicinity of room temperature, beginning with the observations of LaH 10 at 170-190 GPa. However, the pressures required for synthesis of these high-T c superconducting hydrides currently remain extremely high. Here we show the investigation of crystal structures and superconductivity in the La-B-H system under pressure with particle-swarm intelligence structure-searches methods in combination with first-principles calculations. Structures with seven stoichiometries, LaBH, LaBH 4 , LaBH 6 , LaBH 7 , LaBH 8 , La(BH) 3 , and La(BH 4 ) 3 were predicted to become stable under pressure. Remarkably, the hydrogen atoms in LaBH 8 were found to bond with B atoms in a manner that is similar to that in H 3 S. Lattice dynamics calculations indicate that LaBH 7 and LaBH 8 become dynamically stable at pressures as low as 109 and 48 GPa, respectively. Moreover, the two phases were predicted to be superconducting with a critical temperature T c of 93 K and 156 K at 110 GPa and 55 GPa, respectively (μ * = 0.1). The present results provide guidance for future experiments targeting hydride superconductors with both low synthesis pressures and high T c .

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Prediction of high- Tc superconductivity in ternary lanthanum borohydrides

et al. 2021

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“…B 2 H 6 is a highly reactive and versatile reagent and a high-energydensity material at ambient pressure which metallizes and even becomes a superconductor under high pressure [49][50][51][52][53][54][55]. Extensive efforts have been made to investigate their highpressure phase diagram [56,57]. Thus far, two stable boron hydrides have been found (e.g., BH and BH 2 ).…”

Section: Introductionmentioning

confidence: 99%

Phase diagrams and electronic properties of B-S and H-B-S systems under high pressure

Zhang

Lin

et al. 2019

Phys. Rev. B

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Pressure has become an effective way to obtain new materials with desirable properties. Considering the various stoichiometries, wide applications, and unique structures of binary H-S, H-B, and B-S compounds, especially at high pressures, it is worth expecting that they might form ternary compounds with interesting properties as well. Here, phase stabilities of H-B-S ternary compounds, in the pressure range from 0 to 200 GPa, are reliably determined through first-principles unbiased structural search calculations. A hitherto unknown orthorhombic HBS compound with Ama2 symmetry is identified to be stable above 25 GPa, in which B and S atoms alternate to form distorted chains and H atoms are covalently bonded with Bs. With pressure, Ama2 HBS undergoes a semiconductor-to-metal electronic transition and even becomes superconducting. The exploration of the binary B-S phase diagram indicates that B-S compounds tend to decompose into elemental solids above 208 GPa. However, two S-rich phases, B 2 S 3 and BS 2 , are predicted at low pressures, exhibiting semiconducting and metallic properties, respectively. BS 2 shows a calculated T c value of 21.9 K at 200 GPa, becoming a superconductor among bulk binary B-S compounds.

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“…High-pressure crystal structures of Li-Se-H were searched for combining the genetic algorithm (GA) with density functional theory (DFT) calculations, 25,26 which has been successfully applied to many structural searches from simple solids to binary and ternary compounds, and has been proved to be a powerful tool for predicting low-energy structures. [27][28][29][30][31] In this work, the GA predicted structures were further re-optimized at fine accuracy. The calculations of structural relaxations and electronic properties were performed by the DFT method using the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA), implemented in the Cambridge Serial Total Energy Package (CASTEP).…”

Section: Methodsmentioning

confidence: 99%