Machine learning the metastable phase diagram of covalently bonded carbon.
Srilok Srinivasan, Rohit Batra, Duan Luo, Troy Loeffler, Sukriti Manna, Henry Chan, Liuxiang Yang, Wenge Yang, Jianguo Wen, Pierre Darancet, Subramanian K R S Sankaranarayanan
Author Information
Srilok Srinivasan: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA. ORCID
Rohit Batra: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA.
Duan Luo: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA. ORCID
Troy Loeffler: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA.
Sukriti Manna: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA.
Henry Chan: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA. ORCID
Liuxiang Yang: Center for High Pressure Science and Technology Advanced Research, 100193, Beijing, P. R. China. ORCID
Wenge Yang: Center for High Pressure Science and Technology Advanced Research, 100193, Beijing, P. R. China. ORCID
Jianguo Wen: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA. jwen@anl.gov. ORCID
Pierre Darancet: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA. pdarancet@anl.gov. ORCID
Subramanian K R S Sankaranarayanan: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA. skrssank@uic.edu. ORCID
Conventional phase diagram generation involves experimentation to provide an initial estimate of the set of thermodynamically accessible phases and their boundaries, followed by use of phenomenological models to interpolate between the available experimental data points and extrapolate to experimentally inaccessible regions. Such an approach, combined with high throughput first-principles calculations and data-mining techniques, has led to exhaustive thermodynamic databases (e.g. compatible with the CALPHAD method), albeit focused on the reduced set of phases observed at distinct thermodynamic equilibria. In contrast, materials during their synthesis, operation, or processing, may not reach their thermodynamic equilibrium state but, instead, remain trapped in a local (metastable) free energy minimum, which may exhibit desirable properties. Here, we introduce an automated workflow that integrates first-principles physics and atomistic simulations with machine learning (ML), and high-performance computing to allow rapid exploration of the metastable phases to construct "metastable" phase diagrams for materials far-from-equilibrium. Using carbon as a prototypical system, we demonstrate automated metastable phase diagram construction to map hundreds of metastable states ranging from near equilibrium to far-from-equilibrium (400 meV/atom). We incorporate the free energy calculations into a neural-network-based learning of the equations of state that allows for efficient construction of metastable phase diagrams. We use the metastable phase diagram and identify domains of relative stability and synthesizability of metastable materials. High temperature high pressure experiments using a diamond anvil cell on graphite sample coupled with high-resolution transmission electron microscopy (HRTEM) confirm our metastable phase predictions. In particular, we identify the previously ambiguous structure of n-diamond as a cubic-analog of diaphite-like lonsdaelite phase.
References
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[PMID: 21361336]
J Phys Chem Lett. 2022 Feb 24;13(7):1886-1893
[PMID: 35175062]
