Transparent dense sodium

Ma, Yanming; Eremets, M. I.; Oganov, Artem R.; Xie, Yu; Trojan, Ivan; Medvedev, S. A.; Lyakhov, Andriy O.; Valle, M.; Prakapenka, Vitali B.

doi:10.1038/nature07786

Cited by 769 publications

(713 citation statements)

References 28 publications

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“…However, it would be a mistake to take this too exclusively: at very small sizes, clusters adopt structures known only under rather extreme conditions in the bulk. The complex structures now known to be adopted by simple metals such as sodium, lithium, and aluminium under pressure [57][58][59] provide evidence that polymorphism should not only be considered a feature of more complex metals. Signatures of solid-solid transitions have indeed been observed in small sodium clusters, such as the reported two-step melting of Na + 41 [60].…”

Section: Quantum Size Effectsmentioning

confidence: 99%

Cluster melting: new, limiting, and liminal phenomena

Gaston

2018

Advances in Physics: X

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The thermodynamic behaviour of clusters and nanoscale structures is both a challenge to the statistical basis of the theory, and of paramount importance to experiment. In this review, the competing influences that determine the melting temperature and behaviour of small atomic clusters is discussed, with reference to both experiment and theory. The liminal spaces between solid and liquid, the non-scaling and scaling regimes, and the metallic and non-metallic states are discussed, and presented as a primary cause of the emergence of new phenomena. Particular emphasis is given to recent theoretical work that combines each of these liminal regions and enables, through first principles calculations of dynamic atomic interactions in Born Oppenheimer molecular dynamics, the explanation of greater than bulk melting temperatures in certain atomic cluster systems. Some perspective is also given on the important questions in nanoscale thermodynamics that remain to be addressed. ARTICLE HISTORY

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Section: Quantum Size Effectsmentioning

confidence: 99%

Cluster melting: new, limiting, and liminal phenomena

Gaston

2018

Advances in Physics: X

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“…͑6͒ that Brillouin and Jones zone activation by pressure should be present, arising largely from an increase in the density. In addition, we have demonstrated recently that the simple empty-core pseudopotential can be successfully used to explain some aspects of the structural complexity of CaLi 2 under high pressure 8,48 and can account for subtle features in the band structures derived from density functional theory ͑DFT͒ calculations. In spite of its simplicity, this analysis should therefore suffice for the initial argument in this context.…”

Section: Fig 5 How ͑A͒ ͉V͑220͉͒mentioning

confidence: 99%

“…7,8,[11][12][13] However, these methods generally offer little physical insight on why a particular configuration is favored or what reduced parameter space is pertinent to the structure of a class of materials under pressure. To set the problem in context, we note that a synthetic inorganic chemist, well versed in valence rules, is much less frequently bothered by the question "what can be made?," than by "how to make it?"…”

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confidence: 99%

“…For instance, lithium and sodium, or their combination with a second element, have been shown to undergo intricate structural transformations under pressure, in both liquid and solid phases, departing in fascinating ways from close packing. [1][2][3][4][5][6][7][8] The dramatic change in reactivity and emergence of new compounds under pressure provide a productive arena for reexamining and deepening our understanding of the underlying structural principles. [7][8][9][10] Obvious questions arise in this context: what new crystalline compounds might form under pressure and in what structures?…”

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confidence: 99%

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Double-diamond NaAl via pressure: Understanding structure through Jones zone activation

Feng

Hoffmann

Ashcroft

2010

The Journal of Chemical Physics

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Under normal conditions, sodium forms a 1:1 stoichiometric compound with indium, and also with thallium, both in the double-diamond structure. But sodium does not combine with aluminum at all. Could NaAl exist? If so, under what conditions and in which structural types? Instead of beginning with a purely computational and first-principles structure search, we are led to apply the early Brillouin and higher (Jones) zone ideas of the physics determining structural selection. We begin with a brief recapitulation of the higher zone concept as applied to the stability of metals and intermetallic compounds. We then discuss the extension of this concept to problems where density becomes a primary variable, within the second-order band structure approximation. An analysis of the range of applicability of pressure-induced Jones zone activation is presented. The simple NaAl compound serves us as a numerical laboratory for the application of this concept. Higher zone arguments and chemical intuition lead quite naturally to the suggestion that 1:1 compound formation between sodium and aluminum should be favored under pressure and specifically in the double-diamond structure. This is confirmed computationally by density functional theoretic methods within the generalized gradient approximation.

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“…Subsequent computational studies have shown that rather than becoming more free-electron like at high densities, with nuclei sitting in a sea of pressure-ionized electrons, wave function orthogonality, the exclusion principle, and the increasing percentage of the sample volume occupied by the atomic core, can lead to electrons becoming localized between the ion cores, and the formation of complex, electride-like phases [24]. In sodium, perhaps the archetypical freeelectron metal at ambient conditions, this results in a phase transition to a remarkable transparent, insulating state above 180 GPa [25].…”

Section: Introductionmentioning

confidence: 99%

Diamonds on Diamond: structural studies at extreme conditions on the Diamond Light Source

McMahon

2015

Phil. Trans. R. Soc. A.

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Extreme conditions (EC) research investigates how the structures and physical and chemical properties of materials change when subjected to extremes of pressure and temperature. Pressures in excess of one million times atmospheric pressure can be achieved using a diamond anvil cell, and, in combination with high-energy, micro-focused radiation from a third-generation synchrotron such as Diamond, detailed structural information can be obtained using either powder or single-crystal diffraction techniques. Here, I summarize some of the research drivers behind international EC research, and then briefly describe the techniques by which high-quality diffraction data are obtained. I then highlight the breadth of EC research possible on Diamond by summarizing four examples from work conducted on the I15 and I19 beamlines, including a study which resulted in the first research paper from Diamond. Finally, I look to the future, and speculate as to the type of EC research might be conducted at Diamond over the next 10 years.

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Transparent dense sodium

Abstract: , has yet to be experimentally confirmed.Here we show that at pressures of ~200 GPa (∼5.0 fold compression), Na becomes

Cited by 769 publications

References 28 publications

Cluster melting: new, limiting, and liminal phenomena

Cluster melting: new, limiting, and liminal phenomena

Double-diamond NaAl via pressure: Understanding structure through Jones zone activation

Diamonds on Diamond: structural studies at extreme conditions on the Diamond Light Source

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