Sound Velocities in Iron to 110 Gigapascals

Fiquet, G.; Badro, James; Guyot, F.; Requardt, H.; Krisch, M.

doi:10.1126/science.291.5503.468

Cited by 149 publications

(125 citation statements)

References 26 publications

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“…Transition metal nitrides (e.g., PtN, PtN2, IrN2, OsN2) are found to have bulk moduli comparable with those of the traditional superhard materials [606,607]. For IrN2, the measured bulk modulus [K0=428 (12) GPa] is second only to that of diamond (K0=440 GPa).…”

Section: Superhard Materialsmentioning

confidence: 81%

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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: Superhard Materialsmentioning

confidence: 81%

“…Sound velocities of materials at HP to over 1 Mbar have been measured [12,[285][286][287] using HERIX. With single-crystal samples, complete phonon dispersions in the Brillouin zone can be mapped by HERIX at HP [100,288,289].…”

Section: Hp Mev Resolved Inelastic X-ray Scatteringmentioning

confidence: 99%

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

2016

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“…Many different sets of experimental [81][82][83][84][85][86][87][88][89] and theoretical 24, 26, 28-30, 59, 90-94 elastic moduli at ambient or zero temperatures have been reported for ε-Fe. We present our calculated static moduli of nonmagnetic hcp Fe as a function of volume in Fig.…”

Section: Thermoelasticitymentioning

confidence: 99%

First-principles thermal equation of state and thermoelasticity of hcp Fe at high pressures

Sha

Cohen

2010

Phys. Rev. B

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We investigate the equation of state and elastic properties of hcp iron at high pressures and high temperatures using first principles linear response linear-muffin-tin-orbital method in the generalized-gradient approximation. We calculate the Helmholtz free energy as a function of volume, temperature, and volume-conserving strains, including the electronic excitation contributions from band structures and lattice vibrational contributions from quasi-harmonic lattice dynamics. We perform detailed investigations IntroductionIron is one of the most abundant elements in the Earth, and is fundamental to our world. The study of iron at high pressures and high temperatures is of great geophysical interest, since both the Earth's liquid outer core and solid inner core are composed mostly of this element. Although the crystal structure of iron at the extremely high temperature (4000 to 8000 K) and high pressure (330 to 360 GPa) conditions found in the inner core is still under intensive debate, 1-10 the hexagonal-close-packed phase (ε-Fe) is commonly believed to have a wide stability field extending from deep mantle to core conditions, and serves as a starting point for understanding the nature of the inner core. 11 Significant experimental and theoretical efforts have been recently devoted to investigate various properties of hcp iron at high pressures and high temperatures. New high-pressure diamond-anvil-cell techniques have been developed or significantly improved, which makes it possible to reach higher pressures and provide more valuable information on material properties in these extreme states. First-principles based theoretical techniques have been improved in reliability and accuracy, and have been widely used to predicate the high pressure-temperature behavior and provide fundamental understandings to the experiment.Despite intensive investigations, numerous fundamental problems remain unresolved, and many of the current results are mutually inconsistent. 11 The melting line at very high pressures has been one of the most difficult and controversial problems. 12-19Other major problems include possible subsolidus phase transitions 2,4,5,11,20 and the magnetic structure of the dense hexagonal iron. In section II we detail the theoretical methods to perform the first-principles calculations and obtain the thermal properties and elastic moduli. We present the results and related discussions about the thermal equation of state in section III, and about the thermoelasticity in section IV. We conclude with a brief summary in Section V. II. Theoretical methodsThe Helmholtz free energy F for many metals has three major contributionswith V as the volume, T as the temperature, and δ as the strain. E static is the zerotemperature energy of a static lattice, F el is the thermal free energy arising from electronic excitations, and F ph is the lattice vibrational energy contribution. We obtain both E static and F el from first-principles calculations directly, assuming that the eigenvalues for given lattice and nuclear pos...

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“…The knowledge of iron EOS is then essential to the construction of a realistic model of Earth and in particular the description of the transition between the liquid outer core and the solid inner core. Many recent works have been devoted to the structure of Earth's core and the iron EOS in geophysical context [1][2][3][4][5][6][7][8][9]. Iron EOS at pressures higher than reached inside the Earth is also interesting for many reasons.…”

mentioning

confidence: 99%

Equation of State Data for Iron at Pressures beyond 10 Mbar

et al. 2002

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We present equation of state points for iron, in the pressure range 10 -45 Mbar, the first obtained with laser-driven shock waves. The experiment has been performed with the high energy laser Phebus, optically smoothed with Kinoform phase plates. Our results double the set of existing experimental data at very high pressures showing good agreement with the predictions of the quotidian equation of state model and with previous results.

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Sound Velocities in Iron to 110 Gigapascals

Cited by 149 publications

References 26 publications

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

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

First-principles thermal equation of state and thermoelasticity of hcp Fe at high pressures

Equation of State Data for Iron at Pressures beyond 10 Mbar

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