MechElastic: A Python library for analysis of mechanical and elastic properties of bulk and 2D materials

Singh, Sobhit; Lang, Logan; Dovale-Farelo, Viviana; Herath, Uthpala; Tavadze, Pedram; Coudert, François‐Xavier; Romero, Aldo H.

doi:10.1016/j.cpc.2021.108068

Cited by 78 publications

(43 citation statements)

References 101 publications

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“…When SOC effects are considered, the elastic constants of the BiSbS 3 (BiSbSe 3 ) monolayer are reduced to C 11 = 44.83 (41.76), C 22 = 8.42 (8.01), C 12 = 3.92 (3.31), and C 66 = 13.40 (13.60) N/m, indicating that the SOC effects cause elastic softening, which is consistent with a previous study . Both with and without considering the SOC, the elastic constants of these two monolayers satisfy the most general mechanical stability criteria ( C 11 > 0, C 11 C 22 > C 12 2 , and det( C ij ) > 0), , suggesting the mechanical stability of BiSbX 3 (X = S, Se) monolayers. Hence, we have proved the comprehensive stability of these two monolayers from different aspects.…”

supporting

confidence: 88%

Novel Braceletlike BiSbX₃ (X = S, Se) Monolayers with an In-Plane Negative Poisson’s Ratio and Anisotropic Photoelectric Properties

Guo

Zhao²,

et al. 2021

J. Phys. Chem. Lett.

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In this work, we predict two novel two-dimensional (2D) auxetic materials, BiSbX 3 (X = S, Se) monolayers, through first-principles calculations. Attributed to their special braceletlike structure, the in-plane negative Poisson's ratio (NPR) of BiSbS 3 and BiSbSe 3 monolayers are as high as −0.25 and −0.26, respectively. The phonon dispersion calculations, ab initio molecular dynamics simulations, and elastic constants calculations demonstrate that these two monolayers possess excellent dynamic, thermal, and mechanical stabilities. The band gap values of BiSbS 3 and BiSbSe 3 calculated at the HSE level by considering the spin−orbit coupling (SOC) effect are 1.68 and 1.20 eV. The anisotropic carrier mobility and superior optical absorption indicate that they may shine in the next generation of electronic and optoelectronic devices. All of these discoveries not only enrich the types of auxetic materials but also provide a structural reference for designing new auxetic materials on the molecular level. Furthermore, they can provide theoretical guidance for future applications of BiSbX 3 (X = S, Se) monolayers in various fields.

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supporting

confidence: 88%

Novel Braceletlike BiSbX₃ (X = S, Se) Monolayers with an In-Plane Negative Poisson’s Ratio and Anisotropic Photoelectric Properties

Guo

Zhao²,

et al. 2021

J. Phys. Chem. Lett.

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“…In particular, the eigenvalues of the elastic tensor (for elastic stability), as well as the Voigt-Reuss-Hill (VRH) averaged 51 − 53 bulk modulus K and shear modulus G , are computed via the MechElastic python library. 54 , 55 The Vickers hardness H is also evaluated by using Chen’s empirical hardness model: 56 where k = K / G is the Pugh’s ratio. Other empirical hardness models 57 , 58 based on elastic moduli in general produce similar hardness predictions.…”

Section: Computational Methodsmentioning

confidence: 99%

Discovering Superhard B–N–O Compounds by Iterative Machine Learning and Evolutionary Structure Predictions

2022

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We searched for new superhard B–N–O compounds with an iterative machine learning (ML) procedure, where ML models are trained using sample crystal structures from an evolutionary algorithm. We first used cohesive energy to evaluate the thermodynamic stability of varying B x N y O z compositions and then gradually focused on compositional regions with high cohesive energy and high hardness. The results converged quickly after a few iterations. Our resulting ML models show that B x +2 N x O 3 compounds with x ≥ 3 (like B 5 N 3 O 3 , B 6 N 4 O 3 , etc.) are potentially superhard and thermodynamically favorable. Our meta-GGA density functional theory calculations indicate that these materials are also wide bandgap (≥4.4 eV) insulators, with the valence band maximum related to the p-orbitals of nitrogen atoms near vacant sites. This study demonstrates that an iterative method combining ML and ab initio simulations provides a powerful tool for discovering novel materials.

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“…Since the spin-orbit coupling (SOC) effects were found to be negligible in the studied system, SOC was not included in the reported calculations. The elastic and mechanical properties were analyzed using the MechElastic code [126,127]. The exfoliation energy was calculated using four different exchangecorrelation approximations: the (PBE) GGA approximation [123], the SCAN [128] meta-GGA, vdW-DF2 GGA functional [129], and SCAN together with the rVV10 correlation functional (SCAN+rVV10) [130].…”

Section: Methodsmentioning

confidence: 99%

High-temperature phonon-mediated superconductivity in monolayer Mg2B4C2

Singh¹,

Romero²,

Mella³

et al. 2021

Preprint

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A new two-dimensional material -Mg2B4C2, belonging to the family of the conventional superconductor MgB2, is theoretically predicted to exhibit superconductivity with critical temperature T c estimated in the 47-48 K range (predicted using the McMillian-Allen-Dynes formula) without any tuning of external parameters such as doping, strain, or substrate-induced effects. The origin of such a high intrinsic T c is ascribed to the presence of strong electron-phonon coupling and topological Dirac states (which are absent in MgB2) yielding a large density of states at the Fermi level. This material also features a nontrivial electronic band topology exhibiting Dirac points, practically gapless Dirac nodal lines, and topological nontrivial edge states. Consequently, it is a potential candidate for realization of topological superconductivity in 2D. This system is obtained after replacing the chemically active boron layers in MgB2 by chemically inactive boron-carbon layers. Hence, the surfaces of this material are inert. Our calculations confirm the stability of 2D Mg2B4C2. We also find that the key features of this material remain essentially unchanged when its thickness is increased by modestly increasing the number of inner MgB2 layers.

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MechElastic: A Python library for analysis of mechanical and elastic properties of bulk and 2D materials

Cited by 78 publications

References 101 publications

Novel Braceletlike BiSbX₃ (X = S, Se) Monolayers with an In-Plane Negative Poisson’s Ratio and Anisotropic Photoelectric Properties

Novel Braceletlike BiSbX₃ (X = S, Se) Monolayers with an In-Plane Negative Poisson’s Ratio and Anisotropic Photoelectric Properties

Discovering Superhard B–N–O Compounds by Iterative Machine Learning and Evolutionary Structure Predictions

High-temperature phonon-mediated superconductivity in monolayer Mg2B4C2

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MechElastic: A Python library for analysis of mechanical and elastic properties of bulk and 2D materials

Cited by 78 publications

References 101 publications

Novel Braceletlike BiSbX3 (X = S, Se) Monolayers with an In-Plane Negative Poisson’s Ratio and Anisotropic Photoelectric Properties

Novel Braceletlike BiSbX3 (X = S, Se) Monolayers with an In-Plane Negative Poisson’s Ratio and Anisotropic Photoelectric Properties

Discovering Superhard B–N–O Compounds by Iterative Machine Learning and Evolutionary Structure Predictions

High-temperature phonon-mediated superconductivity in monolayer Mg2B4C2

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Product

Resources

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Novel Braceletlike BiSbX₃ (X = S, Se) Monolayers with an In-Plane Negative Poisson’s Ratio and Anisotropic Photoelectric Properties

Novel Braceletlike BiSbX₃ (X = S, Se) Monolayers with an In-Plane Negative Poisson’s Ratio and Anisotropic Photoelectric Properties