Transition Element-Like Chemistry for Potassium Under Pressure

Parker, L.J.; Atou, Toshiyuki; Badding, John V.

doi:10.1126/science.273.5271.95

Cited by 117 publications

(78 citation statements)

References 28 publications

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“…As s-to-d transfer occurs under HP, charge density of the alkali metals increases significantly, allowing alloy formation with transition elements. Several compounds have been reported to form under pressure between K and Ni [98,611] and Ag [612,613]. Recently, a novel Rb-Pt alloy at pressures above 17 GPa has been successfully synthesized [614].…”

Section: High Pressure Chemistrymentioning

confidence: 99%

“…Chemical reactivity needs to be carefully considered in selecting these materials, including possible reactivity changes at HP [98,99]. Most HP experiments are conducted on polycrystalline samples.…”

Section: High Pressure Samplesmentioning

confidence: 99%

“…The question becomes what new "rules" govern chemical bonding, structure, and reactivity at HP? Electron distributions at HP tend to be more delocalized, resulting in a tremendous richness in HP chemistry, including complex phase diagrams of "simple" metals [345,481], new forms of matter [150,199], novel intermetallic compounds [98,463], unexpected stoichiometry [194,581,582], and new noble gas chemistry [458,583,584]. For example, the valence state is usually derived from interatomic distances and the coordination number via bond valence sum rules [585].…”

Section: High Pressure Chemistrymentioning

confidence: 99%

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High-pressure studies with x-rays using diamond anvil cells

2016

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Pressure profoundly alters all states of matter. The symbiotic development of ultrahighpressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and magnetic properties of materials over a wide range of pressure-temperature conditions.

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Section: High Pressure Chemistrymentioning

confidence: 99%

Section: High Pressure Samplesmentioning

confidence: 99%

Section: High Pressure Chemistrymentioning

confidence: 99%

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High-pressure studies with x-rays using diamond anvil cells

2016

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Emergent reduction of electronic state dimensionality in dense ordered Li-Be alloys

Feng

Hennig

Ashcroft

et al. 2008

Nature

124

109

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High pressure is known to influence electronic structure and crystal packing, and can in some cases even induce compound formation between elements that do not bond under ambient conditions [1][2][3] . Here we present a computational study showing that high pressure fundamentally alters the reactivity of the light elements lithium (Li) and beryllium (Be), which are the first of the metals in the condensed state and immiscible under normal conditions 4,5 . We identify four stoichiometric Li x Be 12x compounds that are stable over a range of pressures, and find that the electronic density of states of one of them displays a remarkable steplike feature near the bottom of the valence band and then remains almost constant with increasing energy. These characteristics are typical of a quasi-two-dimensional electronic structure, the emergence of which in a three-dimensional environment is rather unexpected. We attribute this observation to large size differences between the ionic cores of Li and Be: as the density increases, the Li cores start to overlap and thereby expel valence electrons into quasi-two-dimensional layers characterized by delocalized free-particle-like states in the vicinity of Be ions.Our extensive structural search exploring possible Be-Li compound formation under pressure uses two conceptually different approaches. In the first, we propose possible structures on the basis of established chemical/physical heuristics of alloy stability at 1 atmosphere (atm) and/or high pressure. Phenomenological 1-atm binary intermetallic structure maps 6 proved useful in this endeavour. In the second approach, initial structures are formed from randomly generated unit cells and atom positions, and subsequently optimized using density-functional theory (DFT) 7 , with the random search targeting unit cells with 15 or fewer atoms. This combined staticlattice structure search explores the stoichiometries most common in binary intermetallic compounds, including LiBe, LiBe

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“…For example, at high pressures alkali metals can acquire unusual transition-metal properties, such as the conversion of potassium from a conventional alkali metal to one with transition-metal properties via the s to d electron transition [1]. Another example is Cs, which shows s to d electron transfer at ∼3 GPa, and it is expected that this may be a general phenomenon in other elemental metals [2].…”

Section: Introductionmentioning

confidence: 99%

Prediction of a stable half-metal ferromagnetic BaCl solid

2016

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Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=1737ee4c-51ab-4e5d-9d7b-ebc59aa23f2c http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=1737ee4c-51ab-4e5d-9d7b-ebc59aa23f2c The modification of Ba in BaCl compounds from alkaline-metal to transition-and half-metal behavior is explored. High-pressure structural changes in BaCl are predicted using an ab initio structure search method. Dynamically stable bcc and R-3m forms of BaCl are predicted at 15 and 10 GPa, respectively. The BaCl forms are more stable than elemental Ba plus BaCl 2 above ∼10 GPa. Ba in stable BaCl adopts transition-metal properties via an s-d transition. At ambient pressure the fcc structure is ferromagnetic, and the bcc structure is half metallic and ferromagnetic. The transition-metal electronic structure found is sufficient to support superconductivity, with T c as high as 3.4 K near ambient pressure.

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Transition Element-Like Chemistry for Potassium Under Pressure

Cited by 117 publications

References 28 publications

High-pressure studies with x-rays using diamond anvil cells

High-pressure studies with x-rays using diamond anvil cells

Emergent reduction of electronic state dimensionality in dense ordered Li-Be alloys

Prediction of a stable half-metal ferromagnetic BaCl solid

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