High-throughput computational search for two-dimensional binary compounds: Energetic stability versus synthesizability of three-dimensional counterparts
Using first principles calculations, the energetic stability of two-dimensional (2D) binary compounds $XY$ is investigated, where $X$ and $Y$ indicate the metallic element from Li to Pb in the periodic table. Here, 1081 compounds in the buckled honeycomb (BHC), buckled square, B2, L1$_0$, and B$_h$ structures are studied. For the compounds that have negative formation energy in the BHC structure or the compounds that can have the B$_h$ structure, the phonon dispersions of the 2D structures are also calculated. We demonstrate that (i) a negative formation energy is neither a sufficient nor necessary condition for yielding the dynamical stability of 2D compounds; and (ii) if a compound in the B$_h$ structure has been synthesized experimentally, that in the BHC structure is dynamically stable.
Assessing the synthesizability of inorganic materials is a grand challenge for accelerating their discovery using computations. Synthesis of a material is a complex process that depends not only on its thermodynamic stability with respect to others, but also on factors from kinetics, to advances in synthesis techniques, to the availability of precursors. This complexity makes the development of a general theory or first-principles approach to synthesizability currently impractical. Here we show how an alternative pathway to predicting synthesizability emerges from the dynamics of the materials…
First-principles-based materials screening is systematically performed to discover new combinations of chemical elements possibly making shape-memory alloys (SMAs). The B2, D03, and L21 crystal structures are considered as the parent phases, and the 2H and 6M structures are considered as the martensitic phases. 3,384 binary and 3,243 ternary alloys (6,627 in total) with stoichiometric composition ratios are investigated by the materials screening in terms of energetic and dynamical stabilities of the martensitic phases as well as structural compatibility between the parent and the martensitic …
Despite the prevalence of sputter deposition in the microelectronics industry, it has seen very limited applications for graphene electronics. In this letter, we report systematic investigation of the sputtering induced damages in graphene and identify the energetic sputtering gas neutrals as the primary cause of graphene disorder. We further demonstrate a grazing-incidence sputtering configuration that strongly suppresses fast neutral bombardment and retains graphene structure integrity, creating considerably lower damage than electron-beam evaporation. Such sputtering technique yields fully …
We perform a high-throughput screening on phonon-mediated superconductivity in ternary metal diboride structure with alkali, alkaline earth, and transition metals. We find 17 ground states and 78 low-energy metastable phases. From fast calculations of zone-center electron-phonon coupling, 43 compounds are revealed to show electron-phonon coupling strength higher than that of MgB2. An anti-correlation between energetic stability and electron-phonon coupling strength is identified. We suggest two phases, i.e., Li3ZrB8 and Ca3YB8, to be synthesized, which show reasonable energetic stability and s…
The exfoliation energy - quantifying the energy required to extract a two-dimensional (2D) sheet from the surface of a bulk material - is a key parameter determining the synthesizability of 2D compounds. Here, using ab initio calculations, we present a new group of non-van der Waals 2D materials derived from non-layered crystals which exhibit ultra low exfoliation energies. In particular for sulfides, surface relaxations are essential to correctly describe the associated energy gain needed to obtain reliable results. Taking into account long-range dispersive interactions has only a minor effec…
Kernel Learning Assisted Synthesis Condition Exploration for Ternary Spinel
University of Toronto（多伦多大学）；Acceleration Consortium（加速联盟）；National Research Council Canada（加拿大国家研究委员会）；Clean Energy Innovation Research Center（清洁能源创新研究中心）
At ambient pressure tin transforms from its ground-state semi-metal $α$-Sn (diamond structure) phase to the compact metallic $β$-Sn phase at 13$^\circ$C (286K). There may be a further transition to the simple hexagonal $γ$-Sn above 450K. These relatively low transition temperatures are due to the small energy differences between the structures, $\approx 20$\,meV/atom between $α$- and $β$-Sn. This makes tin an exceptionally sensitive test of the accuracy of density functionals and computational methods. Here we use the high-throughput Automatic-FLOW (AFLOW) method to study the energetics of tin…
In this work, high throughput DFT calculations are performed on the alkali metal-based half Heusler alloys; LiY$_p$Y$^\prime_{1-p}$S (Y, Y$^\prime$ = V, Cr, Mn, Fe, Co, Ni and $\mathit{p}$ = 0, 0.25, 0.5, 0.75, 1). Starting with 243 structural replica, systematic filters are designed to select the energetically and vibrationally favorable compositions by considering the contributions stemming from the magnetic alignments of the ions. Thereby, 26 dynamically stable magnetic compositions are identified, of which 10 are found to be ferromagnetic (FM), 4 antiferromagnetic (AFM) and 12 ferrimagneti…
We use high-throughput first-principles sampling to investigate competitive factors that determine the crystal structure of high-entropy alloys (HEAs) and the energetics dependence of the stable phase on the atomic configuration of fully ordered L1$_2$, D0$_{22}$, and random solid solution (RSS) phases of equiatomic quaternary alloys comprising four of the six constituent elements (Cr, Mn, Fe, Co, Ni, and Cu). Considering the configurational entropy, we demonstrate that valence electron concentration (VEC) and temperature are crucial to determine the phase stability of HEAs at finite temperatu…
Traditional materials discovery approaches - relying primarily on laborious experiments - have controlled the pace of technology. Instead, computational approaches offer an accelerated path: high-throughput exploration and characterization of virtual structures. These ventures, performed by automated ab-initio frameworks, have rapidly expanded the volume of programmatically-accessible data, cultivating opportunities for data-driven approaches. Herein, a collection of robust characterization methods are presented, implemented within the Automatic Flow Framework for Materials Discovery (AFLOW), …
$\textit{A priori}$ prediction of phase stability of materials is a challenging practice, requiring knowledge of all energetically-competing structures at formation conditions. Large materials repositories $\unicode{x2014}$ housing properties of both experimental and hypothetical compounds $\unicode{x2014}$ offer a path to prediction through the construction of informatics-based, $\textit{ab-initio}$ phase diagrams. However, limited access to relevant data and software infrastructure has rendered thermodynamic characterizations largely peripheral, despite their continued success in dictating s…
Using density functional theory calculations, many researchers have predicted that various tungsten-nitride compounds WN$_x$ ($x$ > 1) will be "ultra-compressible" or "superhard", $i.e.$ as hard as or harder than diamond. These compounds are predicted to have large bulk and shear moduli (> 200 GPa) and to be elastically and vibrationally stable. Compounds with such desirable properties must be energetically stable against decomposition into other compounds. This stability can only be found after the determination of the convex hull for W$_x$N$_1$$_-$$_x$ lines which connect the lowest enthalpy…
Symmetry-Guided Computational Screening of Two-Dimensional Altermagnets with ab initio Hubbard Corrections
Scuola Internazionale Superiore di Studi Avanzati (SISSA)（高级研究国际学院）；Università degli Studi di Modena e Reggio Emilia（摩德纳和雷焦艾米利亚大学）；Istituto Nanoscienze – CNR, S3（纳米科学研究所 - 意大利国家研究委员会）
Navigating Sparse Singlet Fission Chemical Space: An Intelligent Generative-Predictive Paradigm
Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics, South China Normal University（华南师范大学物理学院）；MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University（华南师范大学）；Guangdong Provincial Engineering Technology Research Center of Low Carbon and Advanced Energy Materials, School of Electronic Science and Engineering (School of Microelectronics), South China Normal University（华南师范大学电子科学与工程学院（微电子学院））
Towards Accurate and Scalable High-throughput MOF Adsorption Screening: Merging Classical Force Fields and Universal Machine Learned Interatomic Potentials
High-Throughput Discovery of Chiral Carbon-Boron Semimetals with Weyl Topology and Phonon-Mediated Superconductivity
University of Science and Technology of China（中国科学技术大学）；Wuhan Institute of Technology（武汉工程大学）；Hefei University of Technology（合肥工业大学）；Hanhai Lingchao Intelligent Computing (Shanghai) Technology Services Co., Ltd.（瀚海凌潮智能计算（上海）科技有限公司）
In this work we perform a systematic calculation of the Fe-Ta phase diagram to discover novel hard magnetic phases. By using structure prediction methods based on evolutionary algorithms, we identify two new energetically stable magnetic structures: a tetragonal Fe$_3$Ta (space group 122) and cubic Fe$_5$Ta (space group 216) binary phases. The tetragonal structure is estimated to have both high saturation magnetization ($μ_0$M$_s$=1.14 T) and magnetocrystalline anisotropy (K$_1$=2.17 MJ/m$^3$) suitable for permanent magnet applications. The high-throughput screening of magneto-crystalline anis…
Boron (B) sheet has been intently studied and various candidates with vacancies have been proposed by theoretical investigations, including the possible growth on metal surface. However, a recent experiment (Science 350, 1513, 2015) reported that the sheet formed on the Ag(111) surface was a buckled triangular lattice without vacancy. Our calculations combined with High-Throughput screening and the first-principles method demonstrate a novel growth mechanism of boron sheet from clusters, ribbons, to monolayers, where the B-Ag interaction is dominant in the nucleation of boron nanostructures. W…
Systematic Magnetic Structure Generation Based on Oriented Spin Space Groups: Formulation, Applications, and High-Throughput First-Principles Calculations
Two-dimensional (2D) materials are strongly affected by the dielectric environment including substrates, making it an important factor in designing materials for quantum and electronic technologies. Yet, first-principles evaluation of charged defect energetics in 2D materials typically do not include substrates due to the high computational cost. We present a general continuum model approach to incorporate substrate effects directly in density-functional theory calculations of charged defects in the 2D material alone. We show that this technique accurately predicts charge defect energies compa…
A thorough in situ characterization of materials at extreme conditions is challenging, and computational tools such as crystal structural search methods in combination with ab initio calculations are widely used to guide experiments by predicting the composition, structure, and properties of high-pressure compounds. However, such techniques are usually computationally expensive and not suitable for large-scale combinatorial exploration. On the other hand, data-driven computational approaches using large materials databases are useful for the analysis of energetics and stability of hundreds of …
Accelerated Inorganic Electrides Discovery by Generative Models and Hierarchical Screening
University of North Carolina at Charlotte（北卡罗来纳大学夏洛特分校）；North Carolina Battery Complexity, Autonomous Vehicle and Electrification (BATT CAVE) Research Center（北卡罗来纳电池复杂性、自动驾驶与电气化（BATT CAVE）研究中心）
