A5042484439- High-pressure geophysics and materials
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Geological and Geochemical Analysis
- Crystal Structures and Properties
- Boron and Carbon Nanomaterials Research
- Diamond and Carbon-based Materials Research
- Inorganic Chemistry and Materials
- Astro and Planetary Science
- Rare-earth and actinide compounds
- Metal and Thin Film Mechanics
- earthquake and tectonic studies
- Geomagnetism and Paleomagnetism Studies
- Advanced Chemical Physics Studies
- Methane Hydrates and Related Phenomena
- MXene and MAX Phase Materials
- Hydrogen Storage and Materials
- Inorganic Fluorides and Related Compounds
- Superconductivity in MgB2 and Alloys
- Hydrocarbon exploration and reservoir analysis
- Geological Studies and Exploration
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Energetic Materials and Combustion
- Spacecraft and Cryogenic Technologies
University of Chicago
2020-2025
Physical Sciences (United States)
2025
Roma Tre University
2024
Argonne National Laboratory
2021-2024
University of Bayreuth
2017-2024
Yonsei University
2022
Arizona State University
2022
Deutsches Elektronen-Synchrotron DESY
2022
Alex's Lemonade Stand Foundation
2021
Bayerisches Landesamt für Umwelt
2019
The discovery of superconducting H
Searching for superconductivity with Tc near room temperature is of great interest both fundamental science & many potential applications. Here we report the experimental discovery maximum critical (Tc) above 210 K in calcium superhydrides, new alkali earth hydrides experimentally showing 200 addition to sulfur hydride rare-earth system. The materials are synthesized at synergetic conditions 160~190 GPa and ~2000 using diamond anvil cell combined in-situ laser heating technique. was studied...
Studies of polynitrogen phases are great interest for fundamental science and the design novel high energy density materials. Laser heating pure nitrogen at 140 GPa in a diamond anvil cell led to synthesis polymeric allotrope with black phosphorus structure, bp-N. The structure was identified situ using synchrotron single-crystal x-ray diffraction further studied by Raman spectroscopy functional theory calculations. discovery bp-N brings line heavier pnictogen elements, resolves...
The layered compound BeN${}_{4}$, berillontirene, is a Dirac semimetal with linear dispersion in the vicinity of Fermi energy and two points coinciding energy, similar to graphene.
In the last few years, superconducting transition temperature, T
Most of the studied two-dimensional (2D) materials are based on highly symmetric hexagonal structural motifs. In contrast, lower-symmetry structures may have exciting anisotropic properties leading to various applications in nanoelectronics. this work we report synthesis nickel diazenide NiN2 which possesses atomic-thick layers comprised Ni2N3 pentagons forming Cairo-type tessellation. The weakly bonded with calculated exfoliation energy 0.72 J/m2, is just slightly larger than that graphene....
Abstract Theoretical modelling predicts very unusual structures and properties of materials at extreme pressure temperature conditions 1,2 . Hitherto, their synthesis investigation above 200 gigapascals have been hindered both by the technical complexity ultrahigh-pressure experiments absence relevant in situ methods analysis. Here we report on a methodology developed to enable static compression terapascal regime with laser heating. We apply this method realize pressures about 600 900...
We predict superconductivity for the carbon--boron clathrate ${\mathrm{SrB}}_{3}{\mathrm{C}}_{3}$ with ${T}_{c}=27\text{--}43\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ Coulomb pseudopotential (${\text{\ensuremath{\mu}}}^{*}$) values between 0.17 and 0.10 using first-principles calculations conventional electron--phonon coupling. Electrical transport measurements, facilitated by an in situ experimental design compatible extreme synthesis conditions ($>3000\phantom{\rule{0.28em}{0ex}}\mathrm{K}$...
The yttrium-hydrogen system has gained attention because of near-ambient temperature superconductivity reports in yttrium hydrides at high pressures. We conducted a study using synchrotron single-crystal x-ray diffraction (SCXRD) 87 to 171 GPa, resulting the discovery known (two YH
Nitrogen catenation under high pressure leads to the formation of polynitrogen compounds with potentially unique properties. The exploration entire spectrum poly- and oligo-nitrogen moieties is still in its earliest stages. Here, we report on four novel scandium nitrides, Sc2N6, Sc2N8, ScN5, Sc4N3, synthesized by direct reaction between yttrium nitrogen at 78-125 GPa 2500 K laser-heated diamond anvil cells. High-pressure synchrotron single-crystal X-ray diffraction reveals that crystal...
Abstract The synthesis of polynitrogen compounds is great importance due to their potential as high‐energy‐density materials (HEDM), but because the intrinsic instability these compounds, and stabilization a fundamental challenge. Polymeric nitrogen units which may be stabilized in with metals at high pressure are now restricted non‐branched chains an average N−N bond order 1.25, limiting HEDM performances. Herein, we demonstrate novel compound TaN 5 via direct reaction between tantalum...
The lanthanum-hydrogen system has attracted significant attention following the report of superconductivity in LaH10 at near-ambient temperatures and high pressures. Phases other than are suspected to be synthesized based on both powder X-ray diffraction resistivity data, although they have not yet been identified. Here, we present results our single-crystal studies this system, supported by density functional theory calculations, which reveal an unexpected chemical structural diversity...
It is challenging to search for high Tc superconductivity (SC) in transition metal elements wherein d electrons are usually not favored by conventional BCS theory. Here we report discovery of surprising SC up 310 GPa with above 20 K wide pressure range from 108 240 titanium. The maximum Tc^onset 26 and zero resistance Tc^zero 21 record values hitherto achieved among element superconductors. Hc2(0) estimated be about 32 Tesla coherence length angstrom. results show strong s-d transfer d-band...
Carbon nitrides featuring three-dimensional frameworks of CN
The recent progress in generating static pressures up to terapascal values opens opportunities for studying novel materials with unusual properties, such as metallization of hydrogen and high-temperature superconductivity. However, an evaluation pressure above ~0.3 is a challenge. We report universal high-pressure scale ~0.5 terapascal, which based on the shift Raman edge stressed diamond anvils correlated equation state Au does not require additional sensor. According new scale, are...
Abstract Polynitrides are intrinsically thermodynamically unstable at ambient conditions and require peculiar synthetic approaches. Now, a one‐step synthesis of metal–inorganic frameworks Hf 4 N 20 ⋅N 2 , WN 8 Os 5 28 ⋅3 via direct reactions between elements in diamond anvil cell pressures exceeding 100 GPa is reported. The porous (Hf ) built from transition‐metal atoms linked either by polymeric polydiazenediyl (polyacetylene‐like) nitrogen chains or through dinitrogen units. Triply bound...
The possibility of high, room-temperature superconductivity was predicted for metallic hydrogen in the 1960s. However, metallization and are yet to be unambiguously demonstrated may require pressures as high 5 million atmospheres. Rare earth based "superhydrides", such LaH10, can considered a close approximation even though they form at moderately lower pressures. In superhydrides predominance H-H bonds superconducting transition temperatures bear hallmarks hydrogen. Still, experimental...
Nanothreads are one-dimensional nanomaterials composed of a primarily sp3 hydrocarbon backbone, typically formed through the compression small molecules to high pressures. Although nanothreads have been synthesized from range precursors, controlling reaction pathways produce atomically precise materials remains difficult challenge. Here, we show how heteroatoms within precursors can serve as "thread-directing" groups by selecting for specific cycloaddition pathways. By using less-reactive...
Abstract Seismic studies have found seismic scatterers with −2 to −12% shear velocity anomalies along some subducting slabs at 700–1900 km depth. The ferroelastic post‐stishovite transition in subducted mid‐ocean ridge basalt (MORB) has been linked these features, but compressional and wave velocities ( V P S ) full elastic moduli C ij of Al,H‐bearing stishovite high pressure remain uncertain. Here we determined Raman shifts optic modes equation state parameters two hydrated Al‐bearing...
Studies on polyhydrides are attracting growing attentions recently due to their potential high temperature superconductivity (SC). We here report the discovery of SC in hafnium at pressures. The superhydrides synthesized pressure and conditions using diamond anvil cell combination with in-situ laser heating technique. was investigated by resistance measurements applied magnetic fields. A superconducting transition onset Tc ∼83 K observed 243 GPa. upper critical field μ0Hc2(0) estimated be 24...