Structure measurements of compressed liquid boron at megabar pressures

Pape, S. Le; Correa, Alfredo A.; Fortmann, C.; Neumayer, P.; Döppner, T.; Davis, P.; Ma, T.; Divol, L.; Plagemann, Kai-Uwe; Schwegler, Eric; Redmer, R.; Glenzer, S. H.

doi:10.1088/1367-2630/15/8/085011

Cited by 7 publications

(10 citation statements)

References 22 publications

(33 reference statements)

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“…The volume selling also occurs in the amorphous form but it is rather small relative to the expansion seen in the liquid state. We need to point out here that the density of liquid B 12 As 2 (2.46 g/cm 3 ) predicted is in reasonable limits considering the density of liquid boron (2.34‐2.4 g/cm 3 ) …”

Section: Discussionmentioning

confidence: 74%

“…We need to point out here that the density of liquid B 12 As 2 (2.46 g/cm 3 ) predicted is in reasonable limits considering the density of liquid boron (2.34-2.4 g/cm 3 ). 29,30 The electronic structure examination exposes that the liquid state is metallic while the amorphous configuration is semiconducting with a band gap of 0.3 eV. Considering the electrical feature of liquid and amorphous B, these findings are also unsurprising because liquid B also shows a metallic behavior 31 while amorphous B is semiconducting.…”

Section: Discussionmentioning

confidence: 99%

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Liquid and amorphous states of boron subarsenide

Durandurdu

2019

J Am Ceram Soc

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Ab initio molecular dynamics simulations are executed to probe the short‐range order and the electrical features of the liquid and amorphous boron subarsenide (B12As2). A drastic volume swelling of ~40% is witnessed for the liquid state, relative to the crystal. The density of the melt is found to be close to that of liquid boron. As the temperature applied is gradually decreased, the volume progressively decreases and a glass‐transition zone at around 1400 K is observed. About 14% volume expansion is perceived for the amorphous phase. Due to the drastic density (volume) difference between the liquid and amorphous forms, their atomic structure is found to be different from each other. In the liquid phase at 2500 K, the mean coordination number (CN) of B and As atoms is 4.4 and 2.5, correspondingly. During the solidification process, both average CNs steadily increase and reach values of 5.5 (B‐atom) and 4.14 (As‐atom) at 300 K. The pentagonal pyramid‐like motifs barely survive at 2500 K but during the quenching process they develop progressively and some of which lead to the formation of B12 clusters. In the amorphous state, the chain‐like and A7‐like As‐As clusters are observed. Nonetheless, the noncrystalline state is proposed to be partially similar to the crystalline structure. The liquid state shows a metallic character while the amorphous form presents a semiconducting nature having an energy band gap much smaller than that of the crystalline phase.

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Section: Discussionmentioning

confidence: 74%

Section: Discussionmentioning

confidence: 99%

Liquid and amorphous states of boron subarsenide

Durandurdu

2019

J Am Ceram Soc

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“…More recently, additional data have been obtained from experiments at large laser facilities, including liquid structure-factor measurements using x-ray radiography to 100-400 GPa [20] and warm dense matter EOS measurements of the Hugoniot at pressures as high as 5608 GPa [1]. Explosive shock experiments have also been performed to measure the electrical conductivity [21] and structural transformation using x-ray diffraction [22] and found amorphization of β boron when shock-compressed to 115 GPa.…”

Section: Introductionmentioning

confidence: 99%

“…Explosive shock experiments have also been performed to measure the electrical conductivity [21] and structural transformation using x-ray diffraction [22] and found amorphization of β boron when shock-compressed to 115 GPa. These recent laser-shock results [1,20] have been compared with highly accurate first-principles electronic structure methods, in particular density functional theory molecular dynamics (DFT-MD). The DFT-MD calculations have shown remarkably good agreement with experimental results for the ionic structure and Hugoniot of liquid boron, and also provided the opportunity to examine other details of the material that are not immediately accessible in shock experiments, such as the Hugoniot temperature and diffusivity.…”

Section: Introductionmentioning

confidence: 99%

Phase transformation in boron under shock compression

Zhang,

Whitley,

Ogitsu

2020

Preprint

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Boron HugoniotPressure (GPa) Density (g/cm 3 ) Marsh,1980 Le Pape,2013 α-B12 β-B106 γ-B28 α-Ga liq.(γ-B28) liq.(α-Ga) Using first-principles molecular dynamics, we calculated the equation of state and shock Hugoniot of various boron phases. We find a large mismatch between Hugoniots based on existing knowledge of the equilibrium phase diagram and those measured by shock experiments, which could be reconciled if the α-B 12 /β → γ-B 28 transition is significantly over-pressurized in boron under shock compression. Our results also indicate that there exists an anomaly and negative Clapeyron slope along the melting curve of boron at 100GPa and 1500-3000 Kelvin. These results enable in-depth understanding of matter under shock compression, in particular the significance of compressionrate dependence of phase transitions and kinetic effects in experimental measurements.

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“…A powerful way to measure these properties is x-ray scattering, and one paper in this collection reports progress in the theory of such effects [30]. Much experimental work is needed to span the enormous range of materials and conditions that are possible, and here we include two examples [31,32].…”

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confidence: 99%

Focus on high energy density physics

Drake

Norreys

2014

New J. Phys.

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High-energy-density physics concerns the behavior of systems at high pressure, often involving the interplay of plasma, relativistic, quantum mechanical and electromagnetic effects. The field is growing rapidly in its scope of activity thanks to advances in experimental, laser and computational technologies. This 'focus on' collection presents papers discussing forefront research that spans the field, providing a sense of its breadth and of the interlinking of its parts.Keywords: High-energy-density physics, warm dense matter, high-pressure matter High-energy-density (HED) physics concerns the behavior of systems roughly characterized as having a pressure above one million atmospheres (equal to 0.1 TPa or 10 12 dynes cm −2 ). More precisely, one might say that it is the laboratory study of matter having a pressure above 0.1 Mbar (10 GPa) and containing free electrons not present in the solid state, and the use of experimental systems that produce such conditions. In principle, this encompasses an indefinite range of conditions, but the realm accessed by current and near-term experiments remains vast, including temperatures from zero (at high enough density) to perhaps 10 12 K, and densities from less than − 10 5 (at high temperature) to 10 4 times the density of water. Quark-gluon plasmas are

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Structure measurements of compressed liquid boron at megabar pressures

Cited by 7 publications

References 22 publications

Liquid and amorphous states of boron subarsenide

Liquid and amorphous states of boron subarsenide

Phase transformation in boron under shock compression

Focus on high energy density physics

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