Defect modeling and control in structurally and compositionally complex materials

Zhang, Xie; Kang, Jun; Wei, Su‐Huai

doi:10.1038/s43588-023-00403-8

Cited by 11 publications

(4 citation statements)

References 149 publications

(162 reference statements)

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“…To ensure that the cation distributions are equilibrated in the MC simulations, we continue the simulations until the thermodynamic quantities, such as energy, converge to within 0.001. We align the atomic correlation functions of supercells with those at a specific temperature to obtain the Special Quasidisordered Structures (SQDS) , at this temperature. We used a 3 × 3 × 3 supercell with 216 atoms and a 4 × 4 × 4 supercell with 192 atoms to build the SQDS of the OCS and MCS, respectively.…”

Section: Methodsmentioning

confidence: 99%

Critical Role of Configurational Disorder in Stabilizing Chemically Unfavorable Coordination in Complex Compounds

Liang,

Li,

Zhou

et al. 2024

J. Am. Chem. Soc.

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The crystal structure of a material is essentially determined by the nature of its chemical bonding. Consequently, the atomic coordination intimately correlates with the degree of ionicity or covalency of the material. Based on this principle, materials with similar chemical compositions can be successfully categorized into different coordination groups. However, counterexamples have recently emerged in complex ternary compounds. For instance, covalent IB-IIIA-VIA 2 compounds, such as AgInS 2 , prefer a tetrahedrally coordinated structure (TCS), while ionic IA-VA-VIA 2 compounds, such as NaBiS 2 , would favor an octahedrally coordinated structure (OCS). One naturally expects that IB-VA-VIA 2 compounds with intermediate ionicity or covalency, such as AgBiS 2 , should then have a mix-coordinated structure (MCS) consisting of covalent AgS 4 tetrahedra and ionic BiS 6 octahedra. Surprisingly, only the experimental presence of the OCS was observed for AgBiS 2 . To resolve this puzzle, we perform first-principles studies of the phase stabilities of ternary compounds at finite temperatures. We find that AgBiS 2 indeed prefers MCS at the ground state, in agreement with the typical expectation, but under experimental synthesis conditions, disordered OCS becomes energetically more favorable because of its low mixing energy and high configurational entropy. Our work elucidates the critical role of configurational disorder in stabilizing chemically unfavorable coordination, providing a rigorous rationale for the anomalous coordination preference in IB-VA-VIA 2 compounds.

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Section: Methodsmentioning

confidence: 99%

Critical Role of Configurational Disorder in Stabilizing Chemically Unfavorable Coordination in Complex Compounds

Liang,

Li,

Zhou

et al. 2024

J. Am. Chem. Soc.

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“…For instance, a metastable state with Δ h f,P = 50 meV, s vib f,P = 5 k B , and S = 1 at 1000 K, we get a prefactor Z 0 / Z b + 0.5 Z 1 / Z b = Z 0 / Z b + 250, so that the predicted concentration may be increased by up to a factor of 250. We note here that there are several non-equilibrium cases where metastable states are also important, such as in solar cells under illumination 50,81,126,128 or materials under electric fields/irradiation, 129 where metastable defect populations can be greatly increased due to kinetic effects. Moreover, metastable states make up the intermediate configurations in defect migration trajectories, so accurately modelling their associated energy surfaces is of key importance for predicting ionic conductivities and kinetic decomposition.…”

Section: Metastable Configurationsmentioning

confidence: 97%

“…This complexity can lead to many inequivalent defect species that need to be considered. 128 Depending on the application, one can envision different strategies to make the problem more tractable.…”

Section: Challenges and Outlooksmentioning

confidence: 99%

Imperfections are not 0 K: free energy of point defects in crystals

et al. 2023

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“…[1][2][3][4][5][6][7][8][9][10] Understanding the properties of semiconductors and the sophisticated microscopic processes and mechanisms that enable the excellent properties are thus at the core of modern semiconductors research. [2,[11][12][13][14][15][16][17] Among the basic properties of semiconductors, their electronic and phononic band structures are of key interest, since various functional properties such as optical absorption and emission, charge and heat transport coefficients, carrier recombination, and thermodynamic free energies can be derived from the basic band structures.…”

mentioning

confidence: 99%

Profiling Electronic and Phononic Band Structures of Semiconductors at Finite Temperatures: Methods and Applications

Zhang 张,

Kang 康,

Wei 魏

2024

Chinese Phys. Lett.

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Semiconductor devices are often operated at elevated temperatures that are well above zero Kelvin, which is the temperature in most first-principles density functional calculations. Computational approaches to computing and understanding the properties of semiconductors at finite temperatures are thus in critical demand. In this review, we discuss the recent progress in computationally assessing the electronic and phononic band structures of semiconductors at finite temperatures. As an emerging semiconductor with particularly strong temperature-induced renormalization of the electronic and phononic band structures, halide perovskites are used as a representative example to demonstrate how computational advances may help to understand the band structures at elevated temperatures. Finally, we briefly illustrate the remaining computational challenges and outlook promising research directions that may help to guide future research in this field.

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Defect modeling and control in structurally and compositionally complex materials

Cited by 11 publications

References 149 publications

Critical Role of Configurational Disorder in Stabilizing Chemically Unfavorable Coordination in Complex Compounds

Critical Role of Configurational Disorder in Stabilizing Chemically Unfavorable Coordination in Complex Compounds

Imperfections are not 0 K: free energy of point defects in crystals

Profiling Electronic and Phononic Band Structures of Semiconductors at Finite Temperatures: Methods and Applications

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