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Carbon and hydrogen are both potential light elements in the Earth's core. However, the stability and elastic properties of Fe‐C‐H ternary alloy under high pressure have rarely been explored. In this study, we synthesized a new hcp‐structured Fe‐C‐H alloy (FeC0.065H1.05) at high pressure using the laser‐heated diamond anvil cell. Hydrogen incorporation significantly expands the volume and decreases the bulk modulus of hcp Fe and Fe‐C alloy (FeC0.065). It also elevates the c/a ratio, potentially explaining the anisotropy of the Earth's inner core. Furthermore, the incorporation of carbon and hydrogen considerably decreases the density of hcp Fe. 0.3–0.7 wt.% H and 0.2–0.5 wt.% C in Fe alloys could account for the observed density deficit of the inner core with 7,000–5,000 K inner core boundary temperature. A tradeoff relationship was established that the effect of 4 wt.% carbon is equivalent to 1 wt.% hydrogen on the density of inner core.

Fe–Ni–S–Si alloy is considered to be one of the plausible candidates of Mercury core material. Elastic properties of Fe–Ni–S–Si liquid are important to reveal the density profile of the Mercury core. In this study, we measured the P-wave velocity ( V P ) of Fe–Ni–S–Si (Fe 73 Ni 10 S 10 Si 7 , Fe 72 Ni 10 S 5 Si 13 , and Fe 67 Ni 10 S 10 Si 13 ) liquids up to 17 GPa and 2000 K to study the effects of pressure, temperature, and multiple light elements (S and Si) on the V P and elastic properties. The V P of Fe–Ni–S–Si liquids are less sensitive to temperature. The effect of pressure on the V P are close to that of liquid Fe and smaller than those of Fe–Ni–S and Fe–Ni–Si liquids. Obtained elastic properties are K S0  = 99.1(9.4) GPa, K S ’  = 3.8(0.1) and ρ 0 =6.48 g/cm 3 for S-rich Fe 73 Ni 10 S 10 Si 7 liquid and K S0  = 112.1(1.5) GPa, K S ’ = 4.0(0.1) and ρ 0 =6.64 g/cm 3 for Si-rich Fe 72 Ni 10 S 5 Si 13 liquid. The V P of Fe–Ni–S–Si liquids locate in between those of Fe–Ni–S and Fe–Ni–Si liquids. This suggests that the effect of multiple light element (S and Si) on the V P is suppressed and cancel out the effects of single light elements (S and Si) on the V P . The effect of composition on the EOS in the Fe–Ni–S–Si system is indispensable to estimate the core composition combined with the geodesy data of upcoming Mercury mission.

At present, a single technical method has difficulty in obtaining microscopic data of ultra-light elements, trace elements, and crystal structures in samples simultaneously. This work combined an in situ focused ion beam—transmission electron microscopy—time of flight secondary ion mass spectrometry (FTT) technique and analyzed the composition and crystal structure of four phyllosilicate samples. These materials were comprised of antigorite, clinochlore, and cookeite phases. An FIB sample preparation technique was found to provide a sample thickness suitable for TEM observations and a degree of surface roughness appropriate for TOF-SIMS analysis. In addition, the relative amounts and distributions of various elements could be obtained, as well as crystal structure data, such that the composition and crystal structure of each specimen were determined. The in situ FTT method demonstrated herein successfully combines the advantages of all three analytical techniques and offers unique advantages with regard to analyzing ultra-light and trace elements as well as the structural data of phyllosilicates.

Light element alloying in iron is required to explain density deficit and seismic wave velocities in Earth’s core. However, the light element composition of the Earth’s core seems hard to constrain as nearly all light element alloying would reduce the density and sound velocity (elastic moduli). The alloying light elements include oxidizing elements like oxygen and sulfur and reducing elements like hydrogen and carbon, yet their chemical effects in the alloy system are less discussed. Moreover, Fe-X-ray Absorption Near Edge Structure (Fe-XANES) fingerprints have been studied for silicate materials with ferrous and ferric ions, while not many X-ray absorption spectroscopy (XAS) studies have focused on iron alloys, especially at high pressures. To investigate the bonding nature of iron alloys in planetary interiors, we presented X-ray absorption spectroscopy of iron–nitrogen and iron–carbon alloys at high pressures up to 50 GPa. Together with existing literature on iron–carbon, –hydrogen alloys, we analyzed their edge positions and found no significant difference in the degree of oxidation among these alloys. Pressure effects on edge positions were also found negligible. Our theoretical simulation of the valence state of iron, alloyed with S, C, O, N, and P also showed nearly unchanged behavior under pressures up to 300 GPa. This finding indicates that the high pressure bonding of iron alloyed with light elements closely resembles bonding at the ambient conditions. We suggest that the chemical properties of light elements constrain which ones can coexist within iron alloys.

The quantification of elemental concentration in cells is usually performed by analytical assays on large populations missing peculiar but important rare cells. The present article aims at comparing the elemental quantification in single cells and cell population in three different cell types using a new approach for single cells elemental analysis performed at sub-micrometer scale combining X-ray fluorescence microscopy and atomic force microscopy. The attention is focused on the light element Mg, exploiting the opportunity to compare the single cell quantification to the cell population analysis carried out by a highly Mg-selective fluorescent chemosensor. The results show that the single cell analysis reveals the same Mg differences found in large population of the different cell strains studied. However, in one of the cell strains, single cell analysis reveals two cells with an exceptionally high intracellular Mg content compared with the other cells of the same strain. The single cell analysis allows mapping Mg and other light elements in whole cells at sub-micrometer scale. A detailed intensity correlation analysis on the two cells with the highest Mg content reveals that Mg subcellular localization correlates with oxygen in a different fashion with respect the other sister cells of the same strain.

Variants of combined technologies for separating isotopes of light chemical elements, using both thermodynamically reversible and irreversible separation methods, are considered from a historical point of view. The main criteria for assessing the efficiency of combining different isotope separation processes are indicated. Based on the specified criteria, a number of problems of obtaining highly enriched carbon-13 and boron-10 isotopes are analyzed.

Thermal management becomes increasingly important as we decrease device size and increase computing power. Engineering materials with high thermal conductivity, such as boron arsenide (BAs), is hard because it is essential to avoid defects and impurities during synthesis, which would stop heat flow. Three different research groups have synthesized BAs with a thermal conductivity around 1000 watts per meter-kelvin: Kang et al. , Li et al. , and Tian et al. succeeded in synthesizing high-purity BAs with conductivities half that of diamond but more than double that of conventional metals (see the Perspective by Dames). The advance validates the search for high-thermal-conductivity materials and provides a new material that may be more easily integrated into semiconducting devices. Science , this issue p. 575 , p. 579 , p. 582 ; see also p. 549 Boron arsenide has an ultrahigh thermal conductivity, making it competitive with diamond for thermal management applications. Conventional theory predicts that ultrahigh lattice thermal conductivity can only occur in crystals composed of strongly bonded light elements, and that it is limited by anharmonic three-phonon processes. We report experimental evidence that departs from these long-held criteria. We measured a local room-temperature thermal conductivity exceeding 1000 watts per meter-kelvin and an average bulk value reaching 900 watts per meter-kelvin in bulk boron arsenide (BAs) crystals, where boron and arsenic are light and heavy elements, respectively. The high values are consistent with a proposal for phonon-band engineering and can only be explained by higher-order phonon processes. These findings yield insight into the physics of heat conduction in solids and show BAs to be the only known semiconductor with ultrahigh thermal conductivity.

Recent series of theoretical and experimental reports have driven attention to time-reversal symmetry-breaking spintronic and spin-splitting phenomena in materials with collinear-compensated magnetic order incompatible with conventional ferromagnetism or antiferromagnetism. Here we employ an approach based on nonrelativistic spin-symmetry groups that resolves the conflicting notions of unconventional ferromagnetism or antiferromagnetism by delimiting a third basic collinear magnetic phase. We derive that all materials hosting this collinear-compensated magnetic phase are characterized by crystal-rotation symmetries connecting opposite-spin sublattices separated in the real space and opposite-spin electronic states separated in the momentum space. We describe prominent extraordinary characteristics of the phase, including the alternating spin-splitting sign and broken time-reversal symmetry in the nonrelativistic band structure, the planar or bulkd-,g-, ori-wave symmetry of the spin-dependent Fermi surfaces, spin-degenerate nodal lines and surfaces, band anisotropy of individual spin channels, and spin-split general, as well as time-reversal invariant momenta. Guided by the spin-symmetry principles, we discover in ab initio calculations outlier materials with an extraordinary nonrelativistic spin splitting, whose eV-scale and momentum dependence are determined by the crystal potential of the nonmagnetic phase. This spin-splitting mechanism is distinct from conventional relativistic spin-orbit coupling and ferromagnetic exchange, as well as from the previously considered anisotropic exchange mechanism in compensated magnets. Our results, combined with our identification of material candidates for the phase ranging from insulators and metals to a parent crystal of cuprate superconductors, underpin research of novel quantum phenomena and spintronic functionalities in high-temperature magnets with light elements, vanishing net magnetization, and strong spin coherence. In the discussion, we argue that the conflicting notions of unconventional ferromagnetism or antiferromagnetism, on the one hand, and our symmetry-based delimitation of the third phase, on the other hand, favor a distinct term referring to the phase. The alternating spin polarizations in both the real-space crystal structure and the momentum-space band structure characteristic of this unconventional magnetic phase suggest a term altermagnetism. We point out thatd-wave altermagnetism represents a realization of the long-sought-after counterpart in magnetism of the unconventionald-wave superconductivity.

Spin current–a flow of electron spins without a charge current–is an ideal information carrier free from Joule heating for electronic devices. The celebrated spin Hall effect, which arises from the relativistic spin-orbit coupling, enables us to generate and detect spin currents in inorganic materials and semiconductors, taking advantage of their constituent heavy atoms. In contrast, organic materials consisting of molecules with light elements have been believed to be unsuited for spin current generation. Here we show that a class of organic antiferromagnets with checker-plate type molecular arrangements can serve as a spin current generator by applying a thermal gradient or an electric field, even with vanishing spin-orbit coupling. Our findings provide another route to create a spin current distinct from the conventional spin Hall effect and open a new field of spintronics based on organic magnets having advantages of small spin scattering and long lifetime. Spin current generation in organic materials is hindered by the light elements in the molecules. Here the authors predict a class of organic antiferromagnets with checker-plate type molecular arrangements can be spin current generator under thermal gradient or an electric field, even without spin-orbit coupling.