67 results on '"Anton O. Oliynyk"'
Search Results
2. Perspective: Web-based machine learning models for real-time screening of thermoelectric materials properties
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Michael W. Gaultois, Anton O. Oliynyk, Arthur Mar, Taylor D. Sparks, Gregory J. Mulholland, and Bryce Meredig
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Biotechnology ,TP248.13-248.65 ,Physics ,QC1-999 - Abstract
The experimental search for new thermoelectric materials remains largely confined to a limited set of successful chemical and structural families, such as chalcogenides, skutterudites, and Zintl phases. In principle, computational tools such as density functional theory (DFT) offer the possibility of rationally guiding experimental synthesis efforts toward very different chemistries. However, in practice, predicting thermoelectric properties from first principles remains a challenging endeavor [J. Carrete et al., Phys. Rev. X 4, 011019 (2014)], and experimental researchers generally do not directly use computation to drive their own synthesis efforts. To bridge this practical gap between experimental needs and computational tools, we report an open machine learning-based recommendation engine (http://thermoelectrics.citrination.com) for materials researchers that suggests promising new thermoelectric compositions based on pre-screening about 25 000 known materials and also evaluates the feasibility of user-designed compounds. We show this engine can identify interesting chemistries very different from known thermoelectrics. Specifically, we describe the experimental characterization of one example set of compounds derived from our engine, RE12Co5Bi (RE = Gd, Er), which exhibits surprising thermoelectric performance given its unprecedentedly high loading with metallic d and f block elements and warrants further investigation as a new thermoelectric material platform. We show that our engine predicts this family of materials to have low thermal and high electrical conductivities, but modest Seebeck coefficient, all of which are confirmed experimentally. We note that the engine also predicts materials that may simultaneously optimize all three properties entering into zT; we selected RE12Co5Bi for this study due to its interesting chemical composition and known facile synthesis.
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- 2016
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3. Revealing Hidden Patterns through Chemical Intuition and Interpretable Machine Learning: A Case Study of Binary Rare-Earth Intermetallics RX
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Volodymyr Gvozdetskyi, Balaranjan Selvaratnam, Anton O. Oliynyk, and Arthur Mar
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General Chemical Engineering ,Materials Chemistry ,General Chemistry - Published
- 2023
4. Tie-Dyeing with Foraged Acorns and Rust: A Workshop Connecting Green Chemistry and Environmental Science
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Christian Machado, Anton O. Oliynyk, and Julian R. Silverman
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General Chemistry ,Education - Published
- 2022
5. Trends in Bulk Compressibility of Mo2–xWxBC Solid Solutions
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Marcus E. Parry, Jackson Hendry, Samantha Couper, Aria Mansouri Tehrani, Anton O. Oliynyk, Jakoah Brgoch, Lowell Miyagi, and Taylor D. Sparks
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General Chemical Engineering ,Materials Chemistry ,General Chemistry - Published
- 2022
6. Ternary Rare-Earth-Metal Nickel Indides RE23Ni7In4 (RE = Gd, Tb, Dy) with Yb23Cu7Mg4-Type Structure
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Griheydi Garcia, Yuriy Tyvanchuk, Matthew Fecica, Anton O. Oliynyk, and Arthur Mar
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Diffraction ,Annealing (metallurgy) ,Rare earth ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,3. Good health ,Inorganic Chemistry ,Pearson symbol ,Metal ,Nickel ,Crystallography ,chemistry ,visual_art ,visual_art.visual_art_medium ,Density functional theory ,Physical and Theoretical Chemistry ,0210 nano-technology ,Ternary operation - Abstract
The ternary rare-earth-metal nickel indides RE23Ni7In4 (RE = Gd, Tb, Dy) were prepared by arc-melting mixtures of the elements followed by annealing at 870 K. They adopt the Yb23Cu7Mg4-type structure (space group P63/mmc, Pearson symbol hP68, Z = 2), as determined by laboratory and synchrotron powder diffraction methods for RE = Gd (a = 9.6435(10) A, c = 22.118(3) A) and Tb (a = 9.5695(8) A, c = 21.983(3) A), and single-crystal X-ray diffraction methods for RE = Dy (a = 9.533(5) A, c = 21.890(13) A). The centrosymmetric Yb23Cu7Mg4-type structure is closely related to the noncentrosymmetric Pr23Ir7Mg4-type structure. Triangular In3 clusters within RE23Ni7In4 represent a rare type of cluster found among metal-rich indides; the reasons for their formation were investigated by density functional theory methods.
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- 2021
7. Machine Learning in Solid‐State Chemistry: Heusler Compounds
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Anton O. Oliynyk, Arthur Mar, and Alexander S. Gzyl
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Solid-state chemistry ,Materials science ,Intermetallic ,Thermodynamics ,Crystal structure - Published
- 2021
8. Green Chemistry Applied to Transition Metal Chalcogenides through Synthesis, Design of Experiments, Life Cycle Assessment, and Machine Learning
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Alexandre H. Pinto, Dylan R. Cho, Anton O. Oliynyk, and Julian R. Silverman
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Transition metal chalcogenides (TMC) is a broad class of materials comprising binary, ternary, quaternary, and multinary oxides, sulfides, selenides, and tellurides. These materials have application in different areas such as solar cells, photocatalysis, sensors, photoinduced therapy, and fluorescent labeling. Due to the technological importance of this class of material, it is necessary to find synthetic methods to produce them through procedures aligned with the Green Chemistry. In this sense, this chapter presents opportunities to make the solution chemistry synthesis of TMC greener. In addition to synthesis, the chapter presents different techniques of experimental planning and analysis, such as design of experiments, life cycle assessment, and machine learning. Then, it explains how Green Chemistry can benefit from each one of these techniques, and how they are related to the Green Chemistry Principles. Focus is placed on binary chalcogenides (sulfides, selenides, and tellurides), and the quaternary sulfide Cu2ZnSnS4 (CZTS), due to its application in many fields like solar energy, photocatalysis, and water splitting. The Green Chemistry synthesis, characterization, and application of these materials may represent sustainable and effective ways to save energy and resources without compromising the quality of the produced material.
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- 2022
9. Significant Variability in the Photocatalytic Activity of Natural Titanium-Containing Minerals: Implications for Understanding and Predicting Atmospheric Mineral Dust Photochemistry
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Devon T. McGrath, Michael J. Katz, Maya Abou-Ghanem, Anton O. Oliynyk, Sarah A. Styler, Andrew J. Locock, Laura C Matchett, and Zhihao Chen
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Anatase ,Ozone ,010504 meteorology & atmospheric sciences ,Photochemistry ,engineering.material ,Mineral dust ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,Environmental Chemistry ,0105 earth and related environmental sciences ,Titanium ,Pollutant ,Minerals ,Atmosphere ,Dust ,General Chemistry ,0104 chemical sciences ,Trace gas ,chemistry ,13. Climate action ,Rutile ,Titanium dioxide ,engineering ,Environmental science ,Ilmenite - Abstract
The billions of tons of mineral dust released into the atmosphere each year provide an important surface for reaction with gas-phase pollutants. These reactions, which are often enhanced in the presence of light, can change both the gas-phase composition of the atmosphere and the composition and properties of the dust itself. Because dust contains titanium-rich grains, studies of dust photochemistry have largely employed commercial titanium dioxide as a proxy for its photochemically active fraction; to date, however, the validity of this model system has not been empirically determined. Here, for the first time, we directly investigate the photochemistry of the complement of natural titanium-containing minerals most relevant to mineral dust, including anatase, rutile, ilmenite, titanite, and several titanium-bearing species. Using ozone as a model gas-phase pollutant, we show that titanium-containing minerals other than titanium dioxide can also photocatalyze trace gas uptake, that samples of the same mineral phase can display very different reactivity, and that prediction of dust photoreactivity based on elemental/mineralogical analysis and/or light-absorbing properties is challenging. Together, these results show that the photochemistry of atmospheric dust is both richer and more complex than previously considered, and imply that a full understanding of the scope and impact of dust-mediated processes will require the community to engage with this complexity via the study of ambient mineral dust samples from diverse source regions.
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- 2020
10. Half-Heusler Structures with Full-Heusler Counterparts: Machine-Learning Predictions and Experimental Validation
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Arthur Mar, Alexander S. Gzyl, and Anton O. Oliynyk
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Materials science ,Condensed matter physics ,010405 organic chemistry ,Group (mathematics) ,Intermetallic ,General Materials Science ,General Chemistry ,Experimental validation ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences - Abstract
Heusler compounds form a diverse group of intermetallic materials encompassing many compositions and structures derived from cubic prototypes, and exhibiting complicated types of disorder phenomena...
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- 2020
11. Machine Learning in Materials Discovery: Confirmed Predictions and Their Underlying Approaches
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Bryce Meredig, James E. Saal, and Anton O. Oliynyk
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Computer science ,business.industry ,Materials informatics ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Machine learning ,computer.software_genre ,01 natural sciences ,0104 chemical sciences ,General Materials Science ,Fraction (mathematics) ,Artificial intelligence ,0210 nano-technology ,business ,computer - Abstract
The rapidly growing interest in machine learning (ML) for materials discovery has resulted in a large body of published work. However, only a small fraction of these publications includes confirmation of ML predictions, either via experiment or via physics-based simulations. In this review, we first identify the core components common to materials informatics discovery pipelines, such as training data, choice of ML algorithm, and measurement of model performance. Then we discuss some prominent examples of validated ML-driven materials discovery across a wide variety of materials classes, with special attention to methodological considerations and advances. Across these case studies, we identify several common themes, such as the use of domain knowledge to inform ML models.
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- 2020
12. Machine Learning for Materials Scientists: An Introductory Guide toward Best Practices
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Ryan J. Murdock, Kristin A. Persson, Jakoah Brgoch, Steven K. Kauwe, Anton O. Oliynyk, Aleksander Gurlo, Taylor D. Sparks, and Anthony Yu-Tung Wang
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Cover (telecommunications) ,Computer science ,General Chemical Engineering ,Best practice ,Materials Chemistry ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences ,Data science ,0104 chemical sciences - Abstract
This Methods/Protocols article is intended for materials scientists interested in performing machine learning-centered research. We cover broad guidelines and best practices regarding the obtaining...
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- 2020
13. Dehydrocoupling – an alternative approach to functionalizing germanium nanoparticle surfaces
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Morteza Javadi, Jonathan G. C. Veinot, Anton O. Oliynyk, Alyxandra N. Thiessen, Asjad Hossain, Nduka Ikpo, and Haoyang Yu
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chemistry.chemical_classification ,Materials science ,Nanoparticle ,chemistry.chemical_element ,Germanium ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Crystallinity ,symbols.namesake ,Chemical engineering ,Heteronuclear molecule ,chemistry ,symbols ,Surface modification ,General Materials Science ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Raman spectroscopy ,Alkyl - Abstract
Surface functionalization is an essential aspect of nanoparticle design and preparation; it can impart stability, processability, functionality, as well as tailor optoelectronic properties that facilitate future applications. Herein we report a new approach toward modifying germanium nanoparticle (GeNP) surfaces and for the first time tether alkyl chains to the NP surfaces through Si-Ge bonds. This was achieved via heteronuclear dehydrocoupling reactions involving alkylsilanes and Ge-H moieties on the NP surfaces. The resulting solution processable RR'2Si-GeNPs (R = octadecyl or PDMS; R' = H or CH3) were characterized using FTIR, Raman, 1H-NMR, XRD, TEM, HAADF, and EELS and were found to retain the crystallinity of the parent GeNP platform.
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- 2020
14. Ternary Rare-Earth-Metal Nickel Indides RE
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Yuriy B, Tyvanchuk, Matthew, Fecica, Griheydi, Garcia, Arthur, Mar, and Anton O, Oliynyk
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The ternary rare-earth-metal nickel indides RE
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- 2021
15. Virtual Issue on Machine-Learning Discoveries in Materials Science
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Jillian M. Buriak and Anton O. Oliynyk
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Multimedia ,General Chemical Engineering ,Materials Chemistry ,General Chemistry ,computer.software_genre ,computer - Published
- 2019
16. Alkaline Earth Metal–Organic Frameworks with Tailorable Ion Release: A Path for Supporting Biomineralization
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Arthur Mar, Michelle Ha, Vladimir K. Michaelis, Mason C Lawrence, Gareth R. Lambkin, Guy M. Bernard, Maria A. Matlinska, Michael J. Katz, Anton O. Oliynyk, Bryden Hughton, and Abishek K. Iyer
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Biomineralization ,Magnetic Resonance Spectroscopy ,Materials science ,Simulated body fluid ,chemistry.chemical_element ,02 engineering and technology ,Calcium ,010402 general chemistry ,01 natural sciences ,Adsorption ,X-Ray Diffraction ,Cell Line, Tumor ,Humans ,Molecule ,General Materials Science ,Dissolution ,Metal-Organic Frameworks ,Ions ,Strontium ,Diphosphonates ,fungi ,Serum Albumin, Bovine ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Demineralization ,Chemical engineering ,chemistry ,0210 nano-technology - Abstract
An innovative application of metal-organic frameworks (MOFs) is in biomedical materials. To treat bone demineralization, which is a hallmark of osteoporosis, biocompatible MOFs (bioMOFs) have been proposed in which various components, such as alkaline-earth cations and bisphosphonate molecules, can be delivered to maintain normal bone density. Multicomponent bioMOFs that release several components simultaneously at a controlled rate thus offer an attractive solution. We report two new bioMOFs, comprising strontium and calcium ions linked by p-xylylenebisphosphonate molecules that release these three components and display no cytotoxic effects on human osteosarcoma cells. Varying the Sr2+/Ca2+ ratio in these bioMOFs causes the rate of ions dissolving into simulated body fluid to be unique; along with the ability to adsorb proteins, this property is crucial for future efforts in drug-release control and promotion of mineral formation. The one-pot synthesis of these bioMOFs demonstrates the utility of MOF design strategies.
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- 2019
17. Atomic Substitution to Balance Hardness, Ductility, and Sustainability in Molybdenum Tungsten Borocarbide
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Jakoah Brgoch, Marcus Parry, Sogol Lotfi, Anton O. Oliynyk, Aria Mansouri Tehrani, Zeshan Rizvi, and Taylor D. Sparks
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Materials science ,Crystal chemistry ,General Chemical Engineering ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Tungsten ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Characterization (materials science) ,chemistry ,Molybdenum ,Materials Chemistry ,Density functional theory ,Orthorhombic crystal system ,Composite material ,0210 nano-technology ,Ductility ,Solid solution - Abstract
Mo2–xWxBC is suggested to be one of the only exceptionally high hardness, transition-metal-rich materials that also shows moderate ductility and compositional sustainability. This is demonstrated here through the synthesis of the Mo2–xWxBC (x = 1.1, 0.75, 0.5, 0.25, 0) solid solution and structural characterization using X-ray diffraction, electron microscopy, and density functional theory. All compounds crystallize in the orthorhombic space group, Cmcm, and follow Vegard’s law. Vickers microindentations show a decrease in hardness as tungsten is substituted by molybdenum owing to changes in the crystal chemistry and the loss of electron density. Calculating Pugh’s ratio based on the values derived from density functional perturbation theory reveals that these materials are surprisingly ductile throughout the solid solution, providing the potential to manipulate the hardness and ductility. Controlling this relationship is of great technological interest as most hard materials suffer from brittleness. More...
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- 2019
18. Synthesis, structure, and properties of rare-earth germanium sulfide iodides RE3Ge2S8I (RE = La, Ce, Pr)
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Arthur Mar, Ebru Üzer, Anton O. Oliynyk, Tom Nilges, Abishek K. Iyer, Dundappa Mumbaraddi, and Vidyanshu Mishra
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chemistry.chemical_classification ,Materials science ,Sulfide ,Band gap ,chemistry.chemical_element ,Germanium ,02 engineering and technology ,Electronic structure ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Ion ,Inorganic Chemistry ,Crystallography ,Paramagnetism ,chemistry ,Materials Chemistry ,Ceramics and Composites ,Physical and Theoretical Chemistry ,0210 nano-technology ,Monoclinic crystal system - Abstract
The rare-earth germanium sulfide iodides RE3Ge2S8I (RE = La, Ce, Pr) have been prepared by reaction of the elements at 900 °C. They adopt the monoclinic La3(SiO4)2Cl-type structure (space group C2/c, Z = 4; a = 16.156(4)–15.9760(9) A, b = 7.9776(18)–7.8786(5) A, c = 11.081(3)–10.9281(6) A, β = 98.192(5)–98.4525(10)° on progressing from La to Pr for the RE component) consisting of isolated thiogermanate tetrahedral groups [GeS4]4– separated by RE3+ and I− ions. The optical band gaps fall in the range of 2.7–3.1 eV. Magnetic measurements indicated simple paramagnetic behaviour for Ce3Ge2S8I and Pr3Ge2S8I.
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- 2019
19. Production of Atmospheric Organosulfates via Mineral-Mediated Photochemistry
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Andrew J. Locock, Sarah A. Styler, Mario Schmidt, Shawn M. Jansen van Beek, Anton O. Oliynyk, and Maya Abou-Ghanem
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chemistry.chemical_classification ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,Hydroxyacetone ,Methacrolein ,010501 environmental sciences ,Mineral dust ,Photochemistry ,01 natural sciences ,Catalysis ,Aerosol ,chemistry.chemical_compound ,chemistry ,Space and Planetary Science ,Geochemistry and Petrology ,Counterion ,Sulfate ,0105 earth and related environmental sciences ,Organosulfate - Abstract
Although organosulfates (ROSO3–) comprise a significant component of secondary organic aerosol (SOA) mass, their atmospheric formation mechanisms are not fully understood. Here, using methacrolein as a model organosulfate precursor, we present a new, mineral-mediated photochemical pathway for organosulfate formation. First, we describe studies of TiO2-catalyzed formation of the atmospherically important organosulfate hydroxyacetone sulfate from methacrolein as a function of illumination time, catalyst loading, sulfate concentration, counterion identity, and methacrolein concentration. Then, we propose a sulfate radical-mediated mechanism for organosulfate formation consistent with these observations. Finally, we show that natural Ti-containing minerals and road dust not only catalyze the formation of comparable amounts of hydroxyacetone sulfate to those formed in the presence of commercial TiO2 but also facilitate the production of additional organosulfate species. These results highlight the complex natu...
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- 2019
20. Lattice strain and texture analysis of superhard Mo0.9W1.1BC and ReWC0.8via diamond anvil cell deformation
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Samantha Couper, Marcus Parry, Anton O. Oliynyk, Jakoah Brgoch, Aria Mansouri Tehrani, Taylor D. Sparks, and Lowell Miyagi
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Diffraction ,Plastic yielding ,Materials science ,Condensed matter physics ,Renewable Energy, Sustainability and the Environment ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Diamond anvil cell ,Lattice strain ,Planar ,Lattice (order) ,General Materials Science ,Orthorhombic crystal system ,0210 nano-technology ,Differential stress - Abstract
Mo0.9W1.1BC and ReWC0.8 compositions have recently been identified to have exceptional hardness and incompressibility. In this work, these compositions are analyzed via in situ radial X-ray diffraction experiments to comparatively assess lattice strain and texture development. Traditionally, Earth scientists have employed these experiments to enhance understanding of dynamic activity within the deep Earth. However, nonhydrostatic compression experiments provide insight into materials with exceptional mechanical properties, as they help elucidate correlations between structural, elastic, and mechanical properties. Here, analysis of differential strain (t/G) and lattice preferred orientation in Mo0.9W1.1BC suggests that dislocation glide occurs along the (010) plane in orthorhombic Mo0.9W1.1BC. The (200) and (002) planes support the highest differential strain, while planes which bisect two or three axes, such as the (110) or (191), exhibit relatively lower differential strain. In ReWC0.8, which crystallizes in a cubic NaCl-type structure, planar density is correlated to orientation-dependent lattice strain as the low-density (311) plane elastically supports more differential strain than the denser (111), (200), and (220) planes. Furthermore, results indicate that ReWC0.8 likely supports a higher differential stress t than Mo0.9W1.1BC and, based on a lack of texture development, bulk plastic yielding is not observed in ReWC0.8 upon compression to ∼60 GPa.
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- 2019
21. Tailorable Indirect to Direct Band-Gap Double Perovskites with Bright White-Light Emission: Decoding Chemical Structure Using Solid-State NMR
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Vladimir K. Michaelis, Alkiviathes Meldrum, Abhoy Karmakar, Anton O. Oliynyk, and Guy M. Bernard
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Photoluminescence ,Chemistry ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Colloid and Surface Chemistry ,Solid-state nuclear magnetic resonance ,Ultraviolet light ,Physical chemistry ,Direct and indirect band gaps ,Light emission ,Spectroscopy ,Perovskite (structure) - Abstract
Efficient white-light-emitting single-material sources are ideal for sustainable lighting applications. Though layered hybrid lead-halide perovskite materials have demonstrated attractive broad-band white-light emission properties, they pose a serious long-term environmental and health risk as they contain lead (Pb2+) and are readily soluble in water. Recently, lead-free halide double perovskite (HDP) materials with a generic formula A(I)2B'(III)B″(I)X6 (where A and B are cations and X is a halide ion) have demonstrated white-light emission with improved photoluminescence quantum yields (PLQYs). Here, we present a series of Bi3+/In3+ mixed-cationic Cs2Bi1-xInxAgCl6 HDP solid solutions that span the indirect to direct band-gap modification which exhibit tailorable optical properties. Density functional theory (DFT) calculations indicate an indirect-direct band-gap crossover composition when x > 0.50. These HDP materials emit over the entire visible light spectrum, centered at 600 ± 30 nm with full-width at half maxima of ca. 200 nm upon ultraviolet light excitation and a maximum PLQY of 34 ± 4% for Cs2Bi0.085In0.915AgCl6. Short-range structural insight for these materials is crucial to unravel the unique atomic-level structural properties which are difficult to distinguish by diffraction-based techniques. Hence, we demonstrate the advantage of using solid-state nuclear magnetic resonance (NMR) spectroscopy to deconvolute the local structural environments of these mixed-cationic HDPs. Using ultrahigh-field (21.14 T) NMR spectroscopy of quadrupolar nuclei (115In, 133Cs, and 209Bi), we show that there is a high degree of atomic-level B'(III)/B″(I) site ordering (i.e., no evidence of antisite defects). Furthermore, a combination of XRD, NMR, and DFT calculations was used to unravel the complete atomic-level random Bi3+/In3+ cationic mixing in Cs2Bi1-xInxAgCl6 HDPs. Briefly, this work provides an advance in understanding the photophysical properties that correlate long- to short-range structural elucidation of these newly developed solid-state white-light emitting HDP materials.
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- 2020
22. Machine Learning for Materials Scientists: An Introductory Guide Towards Best Practices
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Jakoah Brgoch, Kristin A. Persson, Anthony Yu-Tung Wang, Steven K. Kauwe, Ryan J. Murdock, Aleksander Gurlo, Taylor D. Sparks, and Anton O. Oliynyk
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Feature engineering ,Artificial neural network ,business.industry ,Best practice ,Materials informatics ,Benchmarking ,Python (programming language) ,Machine learning ,computer.software_genre ,Subject-matter expert ,Workflow ,Artificial intelligence ,business ,computer ,computer.programming_language - Abstract
This Editorial is intended for materials scientists interested in performing machine learning-centered research.We cover broad guidelines and best practices regarding the obtaining and treatment of data, feature engineering, model training, validation, evaluation and comparison, popular repositories for materials data and benchmarking datasets, model and architecture sharing, and finally publication.In addition, we include interactive Jupyter notebooks with example Python code to demonstrate some of the concepts, workflows, and best practices discussed.Overall, the data-driven methods and machine learning workflows and considerations are presented in a simple way, allowing interested readers to more intelligently guide their machine learning research using the suggested references, best practices, and their own materials domain expertise.
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- 2020
23. A Tale of Seemingly 'Identical' Silicon Quantum Dot Families: Structural Insight into Silicon Quantum Dot Photoluminescence
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Kevin M. O'Connor, Haoyang Yu, Lijuan Zhang, Alkiviathes Meldrum, Anton O. Oliynyk, Alyxandra N. Thiessen, and Jonathan G. C. Veinot
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Physics ,Photoluminescence ,Silicon ,General Chemical Engineering ,Silicon quantum dots ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Engineering physics ,0104 chemical sciences ,chemistry ,Quantum dot ,Computer Science::Multimedia ,Materials Chemistry ,Silicon nanocrystals ,0210 nano-technology ,Quantum - Abstract
Two quantum dots, both alike in composition, but differing in structure, where we lay our scene. From broader classes, to bring deeper understanding, to the crystalline core that drives the quantum dot's sheen. In this contribution we examine two families of silicon quantum dots (SiQDs) that bring to mind the Capulets and the Montagues in Shakespeare’s Romeo and Juliet because of their stark similarities and differences. SiQDs are highly luminescent, heavy-metal-free and based upon earth-abundant elements. As such, they have attracted attention for far reaching applications ranging from biological imaging to luminescent solar concentrators to light-emitting diodes that rely on their size-dependent optical response. Unfortunately, correlating SiQD “size” to their photoluminescence maximum is often challenging. Herein, we provide essential structural insight into the correlation of SiQD dimension and PL maximum through a direct comparison of samples that exhibit statistically identical physical dimensions (dTEM) and chemical compositions, but different crystallite size (dXRD) and PL maxima. We then expand the scope of this investigation and systematically compare groupings of SiQDs: one in which the dXRD and dTEM agree and one where dXRD < dTEM. This latter comparison clearly shows dXRD better predicts SiQD optical response when using the well-established effective mass approximation.
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- 2020
24. Hexagonal Double Perovskite Cs2 AgCrCl6
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Abdelrahman M. Askar, Arthur Mar, Jan-Hendrik Pöhls, Anton O. Oliynyk, Karthik Shankar, Yuqiao Zhou, and Abishek K. Iyer
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Inorganic Chemistry ,Crystallography ,Chemistry ,Hexagonal crystal system ,Halide ,Double perovskite ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences ,0104 chemical sciences - Published
- 2018
25. Not Just Par for the Course: 73 Quaternary Germanides RE4M2XGe4 (RE = La–Nd, Sm, Gd–Tm, Lu; M = Mn–Ni; X = Ag, Cd) and the Search for Intermetallics with Low Thermal Conductivity
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Gabriel M. Duarte, Anton O. Oliynyk, Arthur Mar, Leila Ghadbeigi, Steven K. Kauwe, Abishek K. Iyer, Dong Zhang, and Taylor D. Sparks
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Diffraction ,Chemistry ,Intermetallic ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Metal ,Crystallography ,Thermal conductivity ,Group (periodic table) ,visual_art ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry ,0210 nano-technology ,Electronic band structure ,Solid solution ,Monoclinic crystal system - Abstract
A total of 73 new quaternary rare-earth germanides RE4 M2 XGe4 ( RE = rare-earth metal; M = Mn-Ni; X = Ag, Cd) were prepared through reactions of the elements. The solid solution Nd4Mn2Cd(Ge1- ySi y)4 was also prepared under the same conditions and found to be complete over the entire range. All of these compounds adopt the monoclinic Ho4Ni2InGe4-type structure (space group C2/ m, a = 14.2-16.7 A, b = 4.0-4.6 A, c = 6.8-7.5 A, β = 106-109°), as revealed by powder X-ray diffraction analysis and single-crystal X-ray diffraction analysis on selected members. The structure determination of Nd4(Mn0.78(1)Ag0.22(1))2Ag0.83(1)Ge4 disclosed disorder of Mn and Ag atoms within the tetrahedral site and Ag deficiencies within the square planar site. Within the solid solution Nd4Mn2Cd(Ge1- ySi y)4, the end-members and two intermediate members were structurally characterized; as the Si content increases, the Cd sites become less deficient and the individual [Mn2 Tt2] layers contract but become further apart from each other. Electronic band structure calculations confirm that the Ag-Ge or Cd-Ge bonds are the weakest in the structure and thus prone to distortion. Thermal property measurements confirm expectations from machine-learning predictions that these quaternary germanides should exhibit low thermal conductivity, which was found to be
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- 2018
26. Identifying an efficient, thermally robust inorganic phosphor host via machine learning
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Aria Mansouri Tehrani, Anna C. Duke, Anton O. Oliynyk, Ya Zhuo, and Jakoah Brgoch
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Materials science ,Photoluminescence ,Band gap ,Science ,General Physics and Astronomy ,Quantum yield ,Phosphor ,02 engineering and technology ,010402 general chemistry ,Machine learning ,computer.software_genre ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,law.invention ,symbols.namesake ,law ,lcsh:Science ,Debye model ,Multidisciplinary ,business.industry ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Solid-state lighting ,symbols ,lcsh:Q ,Quantum efficiency ,Density functional theory ,Artificial intelligence ,0210 nano-technology ,business ,computer - Abstract
Rare-earth substituted inorganic phosphors are critical for solid state lighting. New phosphors are traditionally identified through chemical intuition or trial and error synthesis, inhibiting the discovery of potential high-performance materials. Here, we merge a support vector machine regression model to predict a phosphor host crystal structure’s Debye temperature, which is a proxy for photoluminescent quantum yield, with high-throughput density functional theory calculations to evaluate the band gap. This platform allows the identification of phosphors that may have otherwise been overlooked. Among the compounds with the highest Debye temperature and largest band gap, NaBaB9O15 shows outstanding potential. Following its synthesis and structural characterization, the structural rigidity is confirmed to stem from a unique corner sharing [B3O7]5– polyanionic backbone. Substituting this material with Eu2+ yields UV excitation bands and a narrow violet emission at 416 nm with a full-width at half-maximum of 34.5 nm. More importantly, NaBaB9O15:Eu2+ possesses a quantum yield of 95% and excellent thermal stability., Identifying phosphors with good thermal stability and quantum efficiency is a prerequisite to improve the performance of white LED light sources. Here, a combined machine learning and density functional theory method is introduced to identify next generation inorganic phosphors.
- Published
- 2018
27. Polyanionic Gold–Tin Bonding and Crystal Structure Preference in REAu1.5Sn0.5 (RE = La, Ce, Pr, Nd)
- Author
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Anton O. Oliynyk, Sogol Lotfi, and Jakoah Brgoch
- Subjects
education.field_of_study ,Chemistry ,Population ,Intermetallic ,Crystal structure ,Electronic structure ,Electron localization function ,Inorganic Chemistry ,Crystallography ,Density of states ,Orthorhombic crystal system ,Density functional theory ,Physical and Theoretical Chemistry ,education - Abstract
During a systematic search of the RE-Au-Sn (RE = La, Ce, Pr, Nd) ternary phase space, a series of compounds with the general formula REAu1.5Sn0.5 have been identified. These phases can be synthesized by arc melting the elemental metals, followed by annealing. The crystal structures were solved using single-crystal X-ray diffraction, with the composition confirmed by energy-dispersive X-ray spectroscopy. All four compounds crystallize in orthorhombic space group Imma with the CeCu2-type structure. Most notable in these compounds is the polyanionic backbone composed of a single statistically mixed Au/Sn position, which creates a puckered hexagonal bonding network separated by the rare-earth atoms. Electronic structure calculations indicate that the Au 5d bands are dominant in the density of states, while the crystal orbital Hamilton population (-COHP) curves demonstrate Au-Au and Au-Sn interactions, which stabilize the crystal structure. Likewise, a qualitative electron localization function analysis supports the existence of a polyanionic network, and a Bader charge analysis implies anionic character on Au and Sn. The preference for these compounds to adopt the simple CeCu2-type structure is also determined using density functional theory calculations and compared to related compounds to establish a better picture of the unusual behavior of Au in polar intermetallic compounds.
- Published
- 2018
28. Complex Crystal Chemistry of Yb6(CuGa)50 and Yb6(CuGa)51 Grown at Different Synthetic Conditions
- Author
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Sebastian C. Peter, Saurav Ch. Sarma, Soumyabrata Roy, Dundappa Mumbaraddi, Vidyanshu Mishra, Udumula Subbarao, and Anton O. Oliynyk
- Subjects
Valence (chemistry) ,Materials science ,010405 organic chemistry ,Crystal chemistry ,chemistry.chemical_element ,General Chemistry ,Atmospheric temperature range ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,Magnetic susceptibility ,0104 chemical sciences ,Metal ,Crystallography ,chemistry ,Electrical resistivity and conductivity ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,Gallium ,Spectroscopy - Abstract
Two new compounds in the Yb–Cu–Ga system were discovered. Yb6(CuGa)50 was obtained as single crystals grown from gallium metal flux, and Yb6(CuGa)51 was synthesized by high-frequency induction heating technique. Structure analysis reveals new structure type for Yb6(CuGa)50 (C2/m space group), while Yb6(CuGa)51 crystallizes in rhombohedral space group R3m adopting the Th2Zn17 structure type. Both structures could be derived from the simplest layered packing, through CaCu5-type structure, as a common parent. Physical properties of the Yb6(CuGa)51 sample obtained bulk quantity were explored. The magnetic susceptibility study of Yb6(CuGa)51 in the temperature range of 2–300 K suggests a valence fluctuation at lower temperatures. X-ray absorption near edge spectroscopy suggests that Yb exists in mixed-valent state in Yb6(CuGa)51. Electrical resistivity measurement reveals that Yb6(CuGa)51 is metallic in nature and shows Fermi-liquid behavior in the temperature range from 3.5 to 25 K.
- Published
- 2018
29. How To Optimize Materials and Devices via Design of Experiments and Machine Learning: Demonstration Using Organic Photovoltaics
- Author
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Lawrence A. Adutwum, Arthur Mar, Brian C. Olsen, Bing Cao, Jillian M. Buriak, Erik J. Luber, and Anton O. Oliynyk
- Subjects
Organic solar cell ,Process (engineering) ,business.industry ,Multivariable calculus ,Design of experiments ,Photovoltaic system ,General Engineering ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Machine learning ,computer.software_genre ,Interconnectivity ,7. Clean energy ,01 natural sciences ,Uncorrelated ,0104 chemical sciences ,Variable (computer science) ,General Materials Science ,Artificial intelligence ,0210 nano-technology ,business ,computer - Abstract
Most discoveries in materials science have been made empirically, typically through one-variable-at-a-time (Edisonian) experimentation. The characteristics of materials-based systems are, however, neither simple nor uncorrelated. In a device such as an organic photovoltaic, for example, the level of complexity is high due to the sheer number of components and processing conditions, and thus, changing one variable can have multiple unforeseen effects due to their interconnectivity. Design of Experiments (DoE) is ideally suited for such multivariable analyses: by planning one’s experiments as per the principles of DoE, one can test and optimize several variables simultaneously, thus accelerating the process of discovery and optimization while saving time and precious laboratory resources. When combined with machine learning, the consideration of one’s data in this manner provides a different perspective for optimization and discovery, akin to climbing out of a narrow valley of serial (one-variable-at-a-time) experimentation, to a mountain ridge with a 360° view in all directions.
- Published
- 2018
30. Machine Learning Directed Search for Ultraincompressible, Superhard Materials
- Author
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Marcus Parry, Jakoah Brgoch, Feng Lin, Samantha Couper, Aria Mansouri Tehrani, Anton O. Oliynyk, Lowell Miyagi, Zeshan Rizvi, and Taylor D. Sparks
- Subjects
Bulk modulus ,Chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Tungsten ,Rhenium ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Indentation hardness ,Catalysis ,Diamond anvil cell ,0104 chemical sciences ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Tungsten carbide ,Composite material ,0210 nano-technology ,Ternary operation ,Elastic modulus - Abstract
In the pursuit of materials with exceptional mechanical properties, a machine-learning model is developed to direct the synthetic efforts toward compounds with high hardness by predicting the elastic moduli as a proxy. This approach screens 118 287 compounds compiled in crystal structure databases for the materials with the highest bulk and shear moduli determined by support vector machine regression. Following these models, a ternary rhenium tungsten carbide and a quaternary molybdenum tungsten borocarbide are selected and synthesized at ambient pressure. High-pressure diamond anvil cell measurements corroborate the machine-learning prediction of the bulk modulus with less than 10% error, as well as confirm the ultraincompressible nature of both compounds. Subsequent Vickers microhardness measurements reveal that each compound also has an extremely high hardness exceeding the superhard threshold of 40 GPa at low loads (0.49 N). These results show the effectiveness of materials development through state-of-the-art machine-learning techniques by identifying functional inorganic materials.
- Published
- 2018
31. Searching for Missing Binary Equiatomic Phases: Complex Crystal Chemistry in the Hf−In System
- Author
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Martin Hermus, Anton O. Oliynyk, Arthur Mar, Michael W. Gaultois, Jakoah Brgoch, and Andrew J. Morris
- Subjects
Diffraction ,010405 organic chemistry ,Crystal chemistry ,Chemistry ,Binary number ,Thermodynamics ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Tetragonal crystal system ,Group (periodic table) ,Phase (matter) ,Simulated annealing ,Physical and Theoretical Chemistry ,Stoichiometry - Abstract
There remain 21 systems (out of over 3500 possible combinations of the elements) in which the existence of the simple binary equiatomic phases AB has not been established experimentally. Among these, the presumed binary phase HfIn is predicted to adopt the tetragonal CuAu-type structure (space group P4/mmm) by a recently developed machine-learning model and by structure optimization through global energy minimization. To test this prediction, the Hf−In system was investigated experimentally by reacting the elements in a 1:1 stoichiometry at 1070 K. Under the conditions investigated, the bulk and surface of the sample correspond to different crystalline phases but have nearly the same equiatomic composition, as revealed by energy-dispersive X-ray analysis. The structure of the bulk sample, which was solved from powder X-ray diffraction data through simulated annealing, corresponds to the γ-brass (Cu5Zn8) type (space group I43m) with Hf and In atoms disordered over four sites. The structure of crystals sel...
- Published
- 2018
32. Three Rh-rich ternary germanides in the Ce–Rh−Ge system
- Author
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Anton O. Oliynyk, Dong Zhang, and Arthur Mar
- Subjects
Materials science ,Intermetallic ,Crystal structure ,Condensed Matter Physics ,Electron localization function ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,chemistry ,Group (periodic table) ,Materials Chemistry ,Ceramics and Composites ,Orthorhombic crystal system ,Physical and Theoretical Chemistry ,Ternary operation ,Derivative (chemistry) ,Stoichiometry - Abstract
The germanides Ce3Rh11Ge5, Ce6Rh30Ge19.5, and CeRh3Ge2, which are new ternary Rh-rich phases in the Ce–Rh−Ge system, were prepared by reactions of the elements. Their crystal structures were determined by single-crystal and powder X-ray diffraction methods. Ce3Rh11Ge5 adopts the Gd3Ru4Al12-type structure, which represents the fully stoichiometric version of the defect Sc3Ni11Ge4-type structure, in hexagonal space group P63/mmc with Z = 2 and cell parameters a = 8.6964 (12) A and c = 9.2209 (12) A. Ce6Rh30Ge19.5 is a filled derivative of the U6Co30Si19-type structure in hexagonal space group P63/m with Z = 2 and cell parameters a = 22.8480 (11) A and c = 3.9208 (2) A. CeRh3Ge2 is derived from a symmetry-lowered distortion of the hexagonal CeCo3B2-type (or substitutionally ordered CaCu5-type) structure, and crystallizes in orthorhombic space group Fmmm with Z = 16 and cell parameters a = 7.392 (6) A, b = 11.341 (9) A, and c = 19.66 (2) A. As expected by their Rh-rich compositions, the three compounds exhibit extensive Rh–Rh bonding, but surprisingly, they also show some short Ge–Ge contacts. Analysis of the electron localization functions and Bader charges reveals that charge transfer takes place from Ce to Rh atoms, indicative of a polar character in the bonding in these intermetallic compounds.
- Published
- 2021
33. Discovery of Intermetallic Compounds from Traditional to Machine-Learning Approaches
- Author
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Arthur Mar and Anton O. Oliynyk
- Subjects
Computer science ,Serendipity ,business.industry ,02 engineering and technology ,General Medicine ,General Chemistry ,Modular design ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Data science ,0104 chemical sciences ,Knowledge base ,Pattern recognition (psychology) ,0210 nano-technology ,business - Abstract
Intermetallic compounds are bestowed by diverse compositions, complex structures, and useful properties for many materials applications. How metallic elements react to form these compounds and what structures they adopt remain challenging questions that defy predictability. Traditional approaches offer some rational strategies to prepare specific classes of intermetallics, such as targeting members within a modular homologous series, manipulating building blocks to assemble new structures, and filling interstitial sites to create stuffed variants. Because these strategies rely on precedent, they cannot foresee surprising results, by definition. Exploratory synthesis, whether through systematic phase diagram investigations or serendipity, is still essential for expanding our knowledge base. Eventually, the relationships may become too complex for the pattern recognition skills to be reliably or practically performed by humans. Complementing these traditional approaches, new machine-learning approaches may be a viable alternative for materials discovery, not only among intermetallics but also more generally to other chemical compounds. In this Account, we survey our own efforts to discover new intermetallic compounds, encompassing gallides, germanides, phosphides, arsenides, and others. We apply various machine-learning methods (such as support vector machine and random forest algorithms) to confront two significant questions in solid state chemistry. First, what crystal structures are adopted by a compound given an arbitrary composition? Initial efforts have focused on binary equiatomic phases AB, ternary equiatomic phases ABC, and full Heusler phases AB
- Published
- 2017
34. Disentangling Structural Confusion through Machine Learning: Structure Prediction and Polymorphism of Equiatomic Ternary Phases ABC
- Author
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James J. Harynuk, Jakoah Brgoch, Arthur Mar, Anton O. Oliynyk, Lawrence A. Adutwum, Harshil Pisavadia, Viktor Hlukhyy, Brent W. Rudyk, and Sogol Lotfi
- Subjects
Chemistry ,business.industry ,Pattern recognition ,Feature selection ,02 engineering and technology ,General Chemistry ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Class discrimination ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Electronegativity ,Support vector machine ,Colloid and Surface Chemistry ,Polymorphism (materials science) ,Artificial intelligence ,0210 nano-technology ,Valence electron ,Ternary operation ,business - Abstract
A method to predict the crystal structure of equiatomic ternary compositions based only on the constituent elements was developed using cluster resolution feature selection (CR-FS) and support vector machine (SVM) classification. The supervised machine-learning model was first trained with 1037 individual compounds that adopt the most populated ternary 1:1:1 structure types (TiNiSi-, ZrNiAl-, PbFCl-, LiGaGe-, YPtAs-, UGeTe-, and LaPtSi-type) and then validated using an additional 519 compounds. The CR-FS algorithm improves class discrimination and indicates that 113 variables including size, electronegativity, number of valence electrons, and position on the periodic table (group number) influence the structure preference. The final model prediction sensitivity, specificity, and accuracy were 97.3%, 93.9%, and 96.9%, respectively, establishing that this method is capable of reliably predicting the crystal structure given only its composition. The power of CR-FS and SVM classification is further demonstrated by segregating the crystal structure of polymorphs, specifically to examine polymorphism in TiNiSi- and ZrNiAl-type structures. Analyzing 19 compositions that are experimentally reported in both structure types, this machine-learning model correctly identifies, with high confidence (0.7), the low-temperature polymorph from its high-temperature form. Interestingly, machine learning also reveals that certain compositions cannot be clearly differentiated and lie in a "confused" region (0.3-0.7 confidence), suggesting that both polymorphs may be observed in a single sample at certain experimental conditions. The ensuing synthesis and characterization of TiFeP adopting both TiNiSi- and ZrNiAl-type structures in a single sample, even after long annealing times (3 months), validate the occurrence of the region of structural uncertainty predicted by machine learning.
- Published
- 2017
35. Preface to the special issue on machine learning and data-driven design of materials issue in computational materials science
- Author
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Anton O. Oliynyk, Vitaliy Romaka, and Taylor D. Sparks
- Subjects
Computational Mathematics ,General Computer Science ,Mechanics of Materials ,business.industry ,Computer science ,General Physics and Astronomy ,General Materials Science ,General Chemistry ,Computational material science ,Software engineering ,business ,Data-driven - Published
- 2021
36. Solving the Coloring Problem in Half-Heusler Structures: Machine-Learning Predictions and Experimental Validation
- Author
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Lawrence A. Adutwum, Anton O. Oliynyk, Arthur Mar, and Alexander S. Gzyl
- Subjects
Inorganic Chemistry ,010405 organic chemistry ,Data sanitization ,Chemistry ,Sensitivity (control systems) ,Experimental validation ,Physical and Theoretical Chemistry ,Coloring problem ,Total energy ,010402 general chemistry ,01 natural sciences ,Algorithm ,0104 chemical sciences - Abstract
The site preferences within the structures of half-Heusler compounds have been evaluated through a machine-learning approach. A support-vector machine algorithm was applied to develop a model which was trained on 179 experimentally reported structures and 23 descriptors based solely on the chemical composition. The model gave excellent performance, with sensitivity of 93%, selectivity of 96%, and accuracy of 95%. As an illustration of data sanitization, two compounds (GdPtSb, HoPdBi) flagged by the model to have potentially incorrect site assignments were resynthesized and structurally characterized. The predictions of the correct site assignments from the machine-learning model were confirmed by single-crystal and powder X-ray diffraction analysis. These site assignments also corresponded to the lowest total energy configurations as revealed from first-principles calculations.
- Published
- 2019
37. Machine Learning: Finding the Next Superhard Material through Ensemble Learning (Adv. Mater. 5/2021)
- Author
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Blake Day, Jakoah Brgoch, Anton O. Oliynyk, Ziyan Zhang, and Aria Mansouri Tehrani
- Subjects
Materials science ,Mechanics of Materials ,business.industry ,Mechanical Engineering ,Superhard material ,Vickers hardness test ,General Materials Science ,Artificial intelligence ,Machine learning ,computer.software_genre ,business ,computer ,Ensemble learning - Published
- 2021
38. Coloured intermetallic compounds LiCu2Al and LiCu2Ga
- Author
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Arthur Mar, Anton O. Oliynyk, Guillaume Zuber, Dundappa Mumbaraddi, Aurélien Boucheron, Vidyanshu Mishra, Grygoriy Dmytriv, Abishek K. Iyer, Guy M. Bernard, and Vladimir K. Michaelis
- Subjects
Materials science ,Fermi level ,Intermetallic ,02 engineering and technology ,Electronic structure ,Nuclear magnetic resonance spectroscopy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Spectral line ,0104 chemical sciences ,3. Good health ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,NMR spectra database ,symbols.namesake ,Crystallography ,Materials Chemistry ,Ceramics and Composites ,symbols ,Physical and Theoretical Chemistry ,Absorption (chemistry) ,0210 nano-technology ,Electronic band structure - Abstract
The Li-containing intermetallic compounds LiCu2Al and LiCu2Ga were prepared by induction heating. Powder X-ray diffraction revealed cubic structures for these compounds: Li0·5CuAl0.5, CsCl-type ( P m 3 ¯ m , Z = 1, a = 2.9283 (2) A); LiCu2Ga, Heusler or Cu2MnAl-type ( F m 3 ¯ m , Z = 4, a = 5.8617 (4) A). Solid-state 7Li NMR spectra confirmed that the Li atoms are situated on a single site rather than being disordered over multiple sites. Optical reflectance spectra show absorption edges in the visible region consistent with the appearance of colour in these compounds: red for LiCu2Al, yellow for LiCu2Ga. Band structure calculations revealed the presence of completely filled Cu 3d states, and suggest that interband transitions from the top of this narrow band (located around 2.5 eV below the Fermi level) to empty bands are responsible for the colour.
- Published
- 2020
39. High-Throughput Machine-Learning-Driven Synthesis of Full-Heusler Compounds
- Author
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Erin Antono, Taylor D. Sparks, Leila Ghadbeigi, Bryce Meredig, Arthur Mar, Anton O. Oliynyk, Michael W. Gaultois, Gaultois, Michael [0000-0003-2172-2507], and Apollo - University of Cambridge Repository
- Subjects
Materials science ,34 Chemical Sciences ,General Chemical Engineering ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,3402 Inorganic Chemistry ,Thermoelectric effect ,Materials Chemistry ,0210 nano-technology ,Throughput (business) ,True positive rate ,Algorithm - Abstract
A machine-learning model has been trained to discover Heusler compounds, which are intermetallics exhibiting diverse physical properties attractive for applications in thermoelectric and spintronic materials. Improving these properties requires knowledge of crystal structures, which occur in three subtle variations (Heusler, inverse Heusler, and CsCl-type structures) that are difficult, and at times impossible, to distinguish by diffraction techniques. Compared to alternative approaches, this Heusler discovery engine performs exceptionally well, making fast and reliable predictions of the occurrence of Heusler vs non-Heusler compounds for an arbitrary combination of elements with no structural input on over 400 000 candidates. The model has a true positive rate of 0.94 (and false positive rate of 0.01). It is also valuable for data sanitizing, by flagging questionable entries in crystallographic databases. It was applied to screen candidates with the formula AB$_{2}$C and predict the existence of 12 novel gallides MRu$_{2}$Ga and RuM$_{2}$Ga (M = Ti-Co) as Heusler compounds, which were confirmed experimentally. One member, TiRu$_{2}$Ga, exhibited diagnostic superstructure peaks that confirm the adoption of an ordered Heusler as opposed to a disordered CsCl-type structure.
- Published
- 2016
40. Classifying Crystal Structures of Binary Compounds AB through Cluster Resolution Feature Selection and Support Vector Machine Analysis
- Author
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James J. Harynuk, Lawrence A. Adutwum, Arthur Mar, and Anton O. Oliynyk
- Subjects
Basis (linear algebra) ,business.industry ,Chemistry ,General Chemical Engineering ,Binary number ,Feature selection ,Pattern recognition ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Linear discriminant analysis ,01 natural sciences ,0104 chemical sciences ,Support vector machine ,Electronegativity ,Set (abstract data type) ,Materials Chemistry ,Artificial intelligence ,Sensitivity (control systems) ,0210 nano-technology ,business - Abstract
Partial least-squares discriminant analysis (PLS-DA) and support vector machine (SVM) techniques were applied to develop a crystal structure predictor for binary AB compounds. Models were trained and validated on the basis of the classification of 706 AB compounds adopting the seven most common structure types (CsCl, NaCl, ZnS, CuAu, TlI, β-FeB, and NiAs), through data extracted from Pearson’s Crystal Data and ASM Alloy Phase Diagram Database. Out of 56 initial variables (descriptors based on elemental properties only), 31 were selected in as unbiased manner as possible through a procedure of forward selection and backward elimination, with the quality of the model evaluated by measuring the cluster resolution at each step. PLS-DA gave sensitivity of 96.5%, specificity of 66.0%, and accuracy of 77.1% for the validation set data, whereas SVM gave sensitivity of 94.2%, specificity of 92.7%, and accuracy of 93.2%, a significant improvement. Radii, electronegativity, and valence electrons, previously chosen i...
- Published
- 2016
41. Interaction of tantalum, chromium, and phosphorus at 1070 K: Phase diagram and structural chemistry
- Author
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Oksana Toma, Anton O. Oliynyk, Ya. F. Lomnytska, Arthur Mar, Volodymyr Babizhetskyy, and Mariya Dzevenko
- Subjects
Materials science ,Tantalum ,chemistry.chemical_element ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Ternary phase ,01 natural sciences ,Structural chemistry ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Chromium ,Crystallography ,chemistry ,X-ray crystallography ,Materials Chemistry ,Ceramics and Composites ,Physical and Theoretical Chemistry ,0210 nano-technology ,Phase diagram - Abstract
Solid-state phase equilibria have been established in the Ta–Cr–P system in the region of 0–67 at% P at 1070 K through powder X-ray diffraction analysis. Mutual substitution of Ta and Cr in binary phosphides gives rise to significant homogeneity ranges in Ta 1.00–0.66 Cr 0–0.34 P (NbAs-type; a =3.332(3)–3.1366(3) A, c =11.386(4)–11.364(2) A), Ta 3.0–2.1 Cr 0–0.9 P (Ti 3 P-type, a =10.156(2)–9.9992(2) A, c =5.015(1)–4.956(2) A), and Cr 3.0–2.4 Ta 0–0.6 P (Ni 3 P-type, a =9.186(5)–9.217(4) A, c =4.557(3)–4.5911(3) A). A limited homogeneity range is found in the ternary phase Ta 1.0–0.8 Cr 1.0–1.2 P (TiNiSi-type, a =6.2344(5)–6.141(2) A, b =3.5034(3)–3.3769(6) A, c =7.3769(6)–7.357(2) A). The OsGe 2 -type structures (space group C 2/ m ) of a new P-rich compound, Ta 0.92(2) Cr 0.08(2) P 2 ( a =8.8586(3) A, b =3.2670(2) A, c =7.4871(2) A, β =119.315(2)°) as well as of the Ti-containing analogue Ta 0.93(3) Ti 0.07(3) P 2 ( a =8.8592(5) A, b =3.2663(3) A, c =7.4870(5) A, β =119.309(2)°) were refined from powder X-ray diffraction data.
- Published
- 2016
42. Data mining our way to the next generation of thermoelectrics
- Author
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Taylor D. Sparks, Jakoah Brgoch, Anton O. Oliynyk, Bryce Meredig, and Michael W. Gaultois
- Subjects
Materials science ,Mechanical Engineering ,Metals and Alloys ,New materials ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Thermoelectric materials ,computer.software_genre ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Set (abstract data type) ,Materials Science(all) ,Mechanics of Materials ,Informatics ,General Materials Science ,Data mining ,0210 nano-technology ,computer - Abstract
In this article we provide an overview of data mining, informatics, and machine learning approaches for thermoelectrics. We describe how the initial development of a thermoelectric materials database has enabled the creation of a recommendation engine governed by machine learning and how this engine introduces a new paradigm in thermoelectric materials development. Performance probability is generated based on training models. A demonstration of the data mining approach is set forth in a ternary intermetallic system, where we report new materials.
- Published
- 2016
- Full Text
- View/download PDF
43. Not Just Par for the Course: 73 Quaternary Germanides RE
- Author
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Dong, Zhang, Anton O, Oliynyk, Gabriel M, Duarte, Abishek K, Iyer, Leila, Ghadbeigi, Steven K, Kauwe, Taylor D, Sparks, and Arthur, Mar
- Abstract
A total of 73 new quaternary rare-earth germanides RE
- Published
- 2018
44. Polyanionic Gold-Tin Bonding and Crystal Structure Preference in REAu
- Author
-
Sogol, Lotfi, Anton O, Oliynyk, and Jakoah, Brgoch
- Abstract
During a systematic search of the RE-Au-Sn (RE = La, Ce, Pr, Nd) ternary phase space, a series of compounds with the general formula REAu
- Published
- 2018
45. Enhancement in surface mobility and quantum transport of Bi
- Author
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Kyu-Bum, Han, Su Kong, Chong, Anton O, Oliynyk, Akira, Nagaoka, Suzanne, Petryk, Michael A, Scarpulla, Vikram V, Deshpande, and Taylor D, Sparks
- Subjects
Article - Abstract
Despite numerous studies on three-dimensional topological insulators (3D TIs), the controlled growth of high quality (bulk-insulating and high mobility) TIs remains a challenging subject. This study investigates the role of growth methods on the synthesis of single crystal stoichiometric BiSbTeSe2 (BSTS). Three types of BSTS samples are prepared using three different methods, namely melting growth (MG), Bridgman growth (BG) and two-step melting-Bridgman growth (MBG). Our results show that the crystal quality of the BSTS depend strongly on the growth method. Crystal structure and composition analyses suggest a better homogeneity and highly-ordered crystal structure in BSTS grown by MBG method. This correlates well to sample electrical transport properties, where a substantial improvement in surface mobility is observed in MBG BSTS devices. The enhancement in crystal quality and mobility allow the observation of well-developed quantum Hall effect at low magnetic field.
- Published
- 2018
46. The phase equilibria and crystal structure of the phases in the Hf–Ti–P system
- Author
-
Anton O. Oliynyk, Oksana Toma, Ivanna Kushnir, Yaroslava Lomnytska, and Mariya Dzevenko
- Subjects
Materials science ,Phosphide ,Mechanical Engineering ,Metals and Alloys ,PNNM ,Crystal structure ,Crystallography ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,X-ray crystallography ,Materials Chemistry ,Ternary operation ,Powder diffraction ,P system ,Solid solution - Abstract
Phase equilibria in the Hf–Ti–P system were investigated at T = 1070 K in the region 0–67 at.% of P, employing X-ray powder diffraction. The three ternary compounds exist in the Hf–Ti–P system at this temperature. Two of them have homogeneity regions and their compositions can be represented as Hf x Ti 2− x P (0.65 ⩽ x ⩽ 1.30; TiNiSi-type, space group Pnma , a = 6.130(3)–6.673(5), b = 3.508(2)–3.557(2), c = 8.050(5)–8.161(2) A) and Hf x Ti 2− x P 0.68 . (0.75 ⩽ x ⩽ 1.00; Zn 3 Cu-type, space group Р -6, a = 4.758(1)–4.803(1), c = 3.005(1)–3.035(1) A). The crystal structure of the new phosphide Hf 5.35 Ti 8.65 P 8.93 was determined by X-ray single crystal diffraction. This compound crystallizes with the Zr 14 P 9 -type structure (space group Pnnm , cell parameters a = 15.973(1), b = 26.335(2), c = 3.5281(2) A, R 1 = 0.0670; wR 2 = 0.0875). The majority of binary compounds form substitution type solid solutions, in their homogeneity ranges the substitution of Ti by Hf or Hf for Ti takes place.
- Published
- 2015
47. Investigation of phase equilibria in the quaternary Ce–Mn–In–Ge system and isothermal sections of the boundary ternary systems at 800 °C
- Author
-
Arthur Mar, Anton O. Oliynyk, and Kadar Djama-Kayad
- Subjects
Diffraction ,Materials science ,Mechanical Engineering ,Metals and Alloys ,Intermetallic ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Isothermal process ,0104 chemical sciences ,Tetragonal crystal system ,Crystallography ,Ferromagnetism ,Mechanics of Materials ,Materials Chemistry ,Orthorhombic crystal system ,0210 nano-technology ,Ternary operation ,Phase diagram - Abstract
Part of the quaternary Ce–Mn–In–Ge phase diagram has been examined through powder X-ray diffraction and energy-dispersive X-ray analysis. Two new quaternary (Ce 4 Mn 2 InGe 4 and Ce 2 Mn 2 InGe 2 ) and two ternary (Ce 3 Mn 2 Ge 3 and Ce 43 Mn 18 Ge 39 ) phases were found. The isothermal sections of the boundary ternary systems (Ce–Mn–In, Mn–In–Ge, Ce–In–Ge, and Ce–Mn–Ge) were determined at 800 °C. Among these, the Ce–Mn–Ge system deserves particular attention because the phase equilibria are complex. Relative to the previously reported phase diagram evaluated at a lower temperature (400 °C), three ternary phases (CeMn 2 Ge 2 , Ce 2 MnGe 6 , and CeMnGe) persist, Ce 2 MnGe 5 does not form, and two new phases with very close composition (Ce 3 Mn 2 Ge 3 and Ce 43 Mn 18 Ge 39 ) appear at 800 °C. Ce 3 Mn 2 Ge 3 (orthorhombic Hf 3 Ni 2 Si 3 -type) has a small homogeneity range (2%) deviating from the ideal composition, whereas Ce 43 Mn 18 Ge 39 (tetragonal La 2+ x MnGe 2+ y -type) has negligible homogeneity. Magnetic measurements on Ce 4 Mn 2 InGe 4 suggest ferromagnetic behaviour.
- Published
- 2015
48. Ternary rare-earth manganese germanides RE3Mn2Ge3 (RE=Ce–Nd) and a possible oxygen-interstitial derivative Nd4Mn2Ge5O0.6
- Author
-
Anton O. Oliynyk, Kadar Djama-Kayad, and Arthur Mar
- Subjects
Materials science ,Mechanical Engineering ,Metals and Alloys ,Intermetallic ,chemistry.chemical_element ,Crystal structure ,Manganese ,Crystallography ,Octahedron ,chemistry ,Mechanics of Materials ,Materials Chemistry ,Antiferromagnetism ,Orthorhombic crystal system ,Ternary operation ,Monoclinic crystal system - Abstract
The ternary germanides RE 3 Mn 2 Ge 3 , which have been prepared by arc-melting and annealing at 800 °C, are formed with larger rare-earth components (RE = Ce–Nd), in contrast to other RE 3 M 2 Ge 3 series. They adopt the orthorhombic Hf 3 Ni 2 Si 3 -type structure (space group Cmcm , Z = 4). Single-crystal X-ray diffraction studies performed for the Ce member ( a = 4.3340(3) A, b = 11.6069(9) A, c = 14.6717(12) A) indicate an expanded structure relative to other RE 3 M 2 Ge 3 series, with essentially nonbonding Ge–Ge contacts between the [Mn 2 Ge 3 ] layers built up of double-chains of MnGe 4 tetrahedra. A minor oxidation product identified in the course of these investigations was proposed to be Nd 4 Mn 2 Ge 5 O 0.6 , in which a host monoclinic Yb 4 Mn 2 Sn 5 -type structure accommodates interstitial oxygen atoms partially occupying an octahedral void (space group C 2/ m , Z = 2, a = 16.275(3) A, b = 4.3779(8) A, c = 7.3783(14) A, β = 107.372(2)°). This structure also contains layers with double-chains of MnGe 4 tetrahedra which are now connected through Ge 2 dimers; isolated Ge atoms in square planar coordination are located between the layers. Magnetic measurements on RE 3 Mn 2 Ge 3 suggest complex antiferromagnetic ordering phenomena with several field-dependent transitions.
- Published
- 2014
49. Rare-earth transition-metal gallium chalcogenides RE3MGaCh7 (M=Fe, Co, Ni; Ch=S, Se)
- Author
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Brent W. Rudyk, Stanislav S. Stoyko, Anton O. Oliynyk, and Arthur Mar
- Subjects
Materials science ,Space group ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,XANES ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Paramagnetism ,Crystallography ,Octahedron ,Transition metal ,X-ray crystallography ,Materials Chemistry ,Ceramics and Composites ,Antiferromagnetism ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Six series of quaternary rare-earth transition-metal chalcogenides RE3MGaCh7 (M=Fe, Co, Ni; Ch=S, Se), comprising 33 compounds in total, have been prepared by reactions of the elements at 1050 °C (for the sulphides) or 900 °C (for the selenides). They adopt noncentrosymmetric hexagonal structures (ordered Ce3Al1.67S7-type, space group P63, Z=2) with cell parameters in the ranges of a=9.5–10.2 A and c=6.0–6.1 A for the sulphides and a=10.0–10.5 A and c=6.3–6.4 A for the selenides as refined from powder X-ray diffraction data. Single-crystal structures were determined for five members of the sulphide series RE3FeGaS7 (RE=La, Pr, Tb) and RE3CoGaS7 (RE=La, Tb). The highly anisotropic crystal structures consist of one-dimensional chains of M-centred face-sharing octahedra and stacks of Ga-centred tetrahedra all pointing in the same direction. Magnetic measurements on the sulphides reveal paramagnetic behaviour in some cases and long-range antiferromagnetic behaviour with low Neel temperatures (15 K or lower) in others. Ga L-edge XANES spectra support the presence of highly cationic Ga tetrahedral centres with a tendency towards more covalent Ga–Ch character on proceeding from the sulphides to the selenides. Band structure calculations on La3FeGaS7 indicate that the electronic structure is dominated by Fe 3d-based states near the Fermi level.
- Published
- 2014
50. Quaternary rare-earth sulfides RE3M0.5M′S7 (M = Zn, Cd; M′ = Si, Ge)
- Author
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Yuqiao Zhou, Yu Qiu, Manon Heyberger, Yixuan Lin, Arthur Mar, Abishek K. Iyer, and Anton O. Oliynyk
- Subjects
Diffraction ,Materials science ,Band gap ,Rare earth ,02 engineering and technology ,Electronic structure ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Crystallography ,Paramagnetism ,Group (periodic table) ,Materials Chemistry ,Ceramics and Composites ,Physical and Theoretical Chemistry ,0210 nano-technology ,Electronic band structure - Abstract
The four series of quaternary sulfides RE3Zn0.5SiS7 (RE = La–Nd, Sm, Gd–Er), RE3Zn0.5GeS7 (RE = La–Nd, Sm, Gd–Er), RE3Cd0.5SiS7 (RE = La–Nd, Sm, Gd–Ho), and RE3Cd0.5GeS7 (RE = La–Nd, Sm, Gd, Tb) were prepared by reactions of the elements at 1050 °C. Analysis of their powder X-ray diffraction patterns indicates that they adopt the noncentrosymmetric hexagonal La3Mn0.5SiS7-type structure (space group P63, Z = 2). The structures of two Cd-containing members were refined from single-crystal X-ray diffraction data (Gd3Cd0.5SiS7, a = 9.9737(8) A, c = 5.6287(4) A; Gd3Cd0.5GeS7, a = 9.9739(3) A, c = 5.7296(4) A). La3Zn0.5GeS7 melts incongruently above 1300 °C. Ce3Zn0.5GeS7 shows simple paramagnetic behaviour arising from non-interacting Ce3+ species. Optical band gaps of 2.7 eV for La3Cd0.5SiS7, 2.3 eV for La3Cd0.5GeS7, and 1.8 eV for Ce3Zn0.5GeS7 were measured. Band structure calculations on La3Cd0.5SiS7 and La3Cd0.5GeS7 confirm the presence of band gaps whose magnitude is controlled by Si–S or Ge–S bonding interactions.
- Published
- 2019
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