Browsing by Author "Curtarolo, S"

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    Comprehensive search for new phases and compounds in binary alloy systems based on platinum-group metals, using a computational first-principles approach
    (Physical Review X, 2014-02-14) Hart, GLW; Curtarolo, S; Massalski, TB; Levy, O
    We report a comprehensive study of the binary systems of the platinum-group metals with the transition metals, using high-throughput first-principles calculations. These computations predict stability of new compounds in 28 binary systems where no compounds have been reported in the literature experimentally and a few dozen of as-yet unreported compounds in additional systems. Our calculations also identify stable structures at compound compositions that have been previously reported without detailed structural data and indicate that some experimentally reported compounds may actually be unstable at low temperatures. With these results, we construct enhanced structure maps for the binary alloys of platinum-group metals. These maps are much more complete, systematic, and predictive than those based on empirical results alone.
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    First principles study of Ag, Au, and Cu surface segregation in FePt-L 10
    (Applied Physics Letters, 2010-11-29) Chepulskii, RV; Curtarolo, S
    Doping FePt nanoparticles could be a possible approach to achieve high L 10 order and magnetic anisotropy. To address stability, first-principles studies of surface segregation of dilute Ag/Au/Cu solutes at and near the (001)/(100)/(111) surfaces of FePt-L 10 are performed. It is found that a strong surface segregation tendency at first outer layer is present in all the cases. For Cu, segregation is less than half of Ag and Au. Ag and Cu segregate to Fe sites at surfaces and preferentially substitute for Fe in the bulk, whereas Au substitutes for Fe at surfaces and for Fe and Pt in the bulk. © 2010 American Institute of Physics.
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    Ordered magnesium-lithium alloys: First-principles predictions
    (Physical Review B - Condensed Matter and Materials Physics, 2010-01-26) Taylor, RH; Curtarolo, S; Hart, GLW
    Magnesium-lithium (Mg-Li) alloys are among the lightest structural materials. Although considerable work has been done on the Mg-Li system, little is known regarding potential ordered phases. A first and rapid analysis of the system with the high-throughput method reveals an unexpected wealth of potentially stable low-temperature phases. Subsequent cluster expansions constructed for bcc and hcp superstructures extend the analysis and verify our high-throughput results. Of particular interest are those structures with greater than 13 at.% lithium, as they exhibit either partial or complete formation as a cubic structure. Order-disorder transition temperatures are predicted by Monte Carlo simulations to be in the range 200-500 K. © 2010 The American Physical Society.
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    Structure maps for hcp metals from first-principles calculations
    (Physical Review B - Condensed Matter and Materials Physics, 2010-05-10) Levy, O; Hart, GLW; Curtarolo, S
    The ability to predict the existence and crystal type of ordered structures of materials from their components is a major challenge of current materials research. Empirical methods use experimental data to construct structure maps and make predictions based on clustering of simple physical parameters. Their usefulness depends on the availability of reliable data over the entire parameter space. Recent development of high-throughput methods opens the possibility to enhance these empirical structure maps by ab initio calculations in regions of the parameter space where the experimental evidence is lacking or not well characterized. In this paper we construct enhanced maps for the binary alloys of hcp metals, where the experimental data leaves large regions of poorly characterized systems believed to be phase separating. In these enhanced maps, the clusters of noncompound-forming systems are much smaller than indicated by the empirical results alone. © 2010 The American Physical Society.