An ab initio study on liquid silicon carbide

Fernan Saiz

    Research output: Contribution to journalArticleResearch

    1 Citation (Scopus)

    Abstract

    This work presents for the first time the properties of the liquid phase of silicon carbide using ab initio molecular dynamics simulations based on density-functional theory (DFT). Our DFT scheme employs a plane-wave basis to expand the atomic orbitals, pseudopotentials built with the projector augmented wave method, and the local-density approximation to describe the exchange–correlation interactions. With this approach we we determine a melting temperature of the zinc-blend phase of 2678.54 ( ± 41.67) K with a pressure of 0.25 (± 0.40) GPa and a density of 3.06 g/cm3 in good agreement with the experimental normal melting point of 2818.00 (± 40.00) K. At these conditions, the diffusion coefficient of the melt is 6.86 x 10−3 nm2/ps which compares well with the estimated value of 2.46 x 10−3 nm2/ps in the experiments done at atmospheric pressure. Finally, our model shows that silicon carbide has a negative melting curve that qualitatively agrees with experiments, with a slope of -36.93 K/GPa with pressures between 2.56 and 6.48 GPa, which compares well with the -44 K/GPa reported from the laboratory carried out with pressures of up to 7.7 GPa. This work provides a straightforward methodology based on the popular ’Z-method’ to produce liquid systems of silicon carbide, from which amorphous systems can easily be then produced by quenching.
    Original languageEnglish
    Article number109204
    Number of pages7
    JournalJournal of Physics and Chemistry of Solids
    Volume137
    DOIs
    Publication statusPublished - 1 Feb 2020

    Keywords

    • Ab initio molecular dynamics
    • Density functional theory
    • Materials under extreme conditions
    • Phase transitions
    • Silicon carbide
    • MOLECULAR-DYNAMICS
    • CARBON
    • STABILITY
    • AMORPHIZATION
    • ION
    • TOTAL-ENERGY CALCULATIONS

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