Charting the complete elastic properties of inorganic crystalline compounds

Jong, M. de; Chen, Wei; Angsten, Thomas; Jain, Anubhav; Notestine, Randy; Gamst, Anthony; Sluiter, Marcel H. F.; Ande, Chaitanya Krishna; Zwaag, Sybrand van der; Plata, José J.; Toher, Cormac; Curtarolo, Stefano; Ceder, Gerbrand; Persson, Kristin A.; Asta, Mark

doi:10.1038/sdata.2015.9

Cited by 805 publications

(614 citation statements)

References 79 publications

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“…PBE gives equilibrium lattice parameters of a ¼ 4.47 and c ¼ 31.15 Å. These values agree well with the previous results (a ¼ 4.45, c ¼ 31.15 Å) using the PBE functional [37], and are only 1.8% and 3.3% larger than the experimental values of a ¼ 4.39 and c ¼ 30.50 Å at 300 K, respectively [38].…”

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confidence: 81%

Superstrengthening Bi2Te3 through Nanotwinning

Aydemir

Morozov

et al. 2017

Phys. Rev. Lett.

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Bismuth telluride (Bi 2 Te 3 ) based thermoelectric (TE) materials have been commercialized successfully as solid-state power generators, but their low mechanical strength suggests that these materials may not be reliable for long-term use in TE devices. Here we use density functional theory to show that the ideal shear strength of Bi 2 Te 3 can be significantly enhanced up to 215% by imposing nanoscale twins. We reveal that the origin of the low strength in single crystalline Bi 2 Te 3 is the weak van der Waals interaction between the Te1 coupling two Te1─Bi─Te2─Bi─Te1 five-layer quint substructures. However, we demonstrate here a surprising result that forming twin boundaries between the Te1 atoms of adjacent quints greatly strengthens the interaction between them, leading to a tripling of the ideal shear strength in nanotwinned Bi 2 Te 3 (0.6 GPa) compared to that in the single crystalline material (0.19 GPa). This grain boundary engineering strategy opens a new pathway for designing robust Bi 2 Te 3 TE semiconductors for high-performance TE devices. DOI: 10.1103/PhysRevLett.119.085501 The continued use of fossil fuels to satisfy escalating global energy requirements is causing severe unacceptable environmental impact. This has generated renewed interest in thermoelectric (TE) conversion technology to convert waste heat directly into electricity, which involves no CO 2 production, is scalable to large power plants, and involves no moving parts (silent) [1]. Over the past two decades, the conversion efficiency (zT) of TE materials has enhanced remarkably, approaching to ∼1.8 [2-4], putting TE materials on the threshold of commercial applications. However, under severe operation conditions, TE materials suffer from unavoidable thermomechanical stresses from cycling of the temperature gradients, leading to rapid deterioration of material performance and accelerated failure of TE devices [5][6][7]. In order for thermoelectrics to play a significant role in engineering applications to alternative energy, the strength and the toughness must be dramatically enhanced.Industrial low temperature waste heat accounts for almost one-third of total energy consumption [8]. The bismuth telluride (Bi 2 Te 3 ) state-of-the-art TE material has been widely used for TE refrigeration in this temperature range (300-550 K) [9], and is now being considered in the automotive industry for recovering waste heat from exhaust systems. Traditional elemental doping strategies have been successful in significantly improving TE properties [10,11], but they have had little effect on enhancing the mechanical properties [12]. Recently, nano-SiC particles dispersed in Bi 2 Te 3 were reported to enhance mechanical strength compared to pure Bi 2 Te 3 , but with concomitant deterioration of the electronic transport properties [13].A well-known mechanism for strengthening metal alloys is to increase the number of such interfacial boundaries as grain boundaries (GBs) and twin boundaries (TBs). These boundaries can strengthen the material by pinning...

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confidence: 81%

Superstrengthening Bi2Te3 through Nanotwinning

Aydemir

Morozov

et al. 2017

Phys. Rev. Lett.

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“…21 A cut-o↵ for the plane waves of 520 eV is used and a uniform k-point density of approximately 1,000 per reciprocal atom is employed. We note that the computational and convergence parameters were chosen consistently with the settings used in the Materials Project 16,22 to enable direct comparisons with the large set of available MP data.…”

Section: Introductionmentioning

confidence: 99%

Computational Approach for Epitaxial Polymorph Stabilization through Substrate Selection

Ding

Dwaraknath

Garten

et al. 2016

ACS Appl. Mater. Interfaces

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With the ultimate goal of finding new polymorphs through targeted synthesis conditions and techniques, we outline a computational framework to select optimal substrates for epitaxial growth using first principle calculations of formation energies, elastic strain energy and topological information. To demonstrate the approach, we study the stabilization of metastable VO 2 compounds which provides a rich chemical as well as structural polymorph space. We find that common polymorph statistics, lattice matching and energy above hull considerations recommends homostructural growth on TiO 2 substrates, where the VO 2 brookite phase would be preferentially grown on the a -c TiO 2 brookite plane while the columbite and anatase structures favor the a -b 1 plane on the respective TiO 2 phases. Overall, we find that a model which incorporates a geometric unit cell area matching between the substrate and the target film as well as the resulting strain energy density of the film provide qualitative agreement with experimental observations for the heterostructural growth of known VO 2 polymorphs: rutile A-and B phases. The minimal interfacial geometry matching and estimated strain energy criteria provide several suggestions for substrates and substrate-film orientations for the heterostructural growth of the hitherto hypothetical anatase, brookite and columbite polymorphs. These criteria serve as a preliminary guidance for the experimental e↵orts stabilizing new materials and/or polymorphs through epitaxy. The current screening algorithm is being integrated within the Materials Project online framework and data and hence publicly available.

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“…Such independent knowledge on the elastic constants can be obtained, for instance, by ab initio calculations [2] and has recently become a routine activity [3].…”

Section: Introductionmentioning

confidence: 99%

Solving the Christoffel equation: Phase and group velocities

Jaeken

Cottenier

2016

Computer Physics Communications

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We provide christoffel, a Python tool for calculating direction-dependent phase velocities, polarization vectors, group velocities, power flow angles and enhancement factors based on the stiffness tensor of a solid. It is built in a modular way to allow for efficient and flexible calculations, and the freedom to select and combine results as desired. All derivatives are calculated analytically, which circumvents possible numerical sampling problems. GNUPlot scripts are provided for convenient visualization. Keywords

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Charting the complete elastic properties of inorganic crystalline compounds

Cited by 805 publications

References 79 publications

Superstrengthening Bi2Te3 through Nanotwinning

Superstrengthening Bi2Te3 through Nanotwinning

Computational Approach for Epitaxial Polymorph Stabilization through Substrate Selection

Solving the Christoffel equation: Phase and group velocities

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