Two novel large-cell boron nitride polymorphs

Fan, Qingyang; Ai, Xin; Song, Yanxing; Yu, Xinhai; Yun, Sining

doi:10.1016/j.diamond.2022.109046

Cited by 8 publications

(4 citation statements)

References 65 publications

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“…As long as the shape of the threedimensional view of Young's modulus of a material is not spherical, it can be considered anisotropic. 64 The size of the deviation from the spherical angle can represent the anisotropy in Young's modulus, 14,16,17,19,22 which can be represented by the ratio of the maximum value to the minimum value of Young's modulus (E max :E min ratio). The anisotropy in Young's modulus of materials may have nothing to do with the crystal symmetry system.…”

Section: Resultsmentioning

confidence: 99%

“…In particular, many important achievements have been made in the exploration of superhard materials and electronic materials for light elements. − As a new generation of semiconductor materials, 3C BN can not only be used to fabricate electronic devices under extreme conditions such as high temperature, high frequency, and high power but also have wide application prospects in deep ultraviolet luminescence and detectors. Boron nitride materials may exhibit excellent properties of superhardness, − ductility, − , an ultrawide bandgap, − or, more rarely, the electronic property of metallicity. − …”

Section: Introductionmentioning

confidence: 99%

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BN Polymorphs in Hexagonal 2–7 Stacking Orders: First-Principles and High-Throughput Study

Fan,

Zhao,

Zhao

et al. 2023

Crystal Growth & Design

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BN polymorphs are important basic materials in superhard materials, as well as in other industrial fields and in microelectronics. The ground-state phase of BN polymorphs has a 3C stacking order. In addition to 3C, eight BN polymorphs (2H, 4H, 5H, 6H-I, 6H-II, 7H-I, 7H-II, and 7H-III) are produced by a random sampling strategy combined with group theory and graph theory (RG 2 ) in this work. It is found that the stack order of 2−7H BN polymorphs is basically similar to that of 3C BN, although with a slight difference. The calculated total energy of these 2−7H BN polymorphs is only 4−17 meV/atoms higher than that of 3C BN, and they are all dynamically and mechanically stable. In addition, their thermal stability at 1000 K is also studied by ab initio molecular dynamics (AIMD) techniques. A combination of tensile stress and hardness is sufficient to prove that BN is a superhard material in 2−7H BN polymorphs. The band gaps of 2−7H BN polymorphs are in the range of 6.19−6.98 eV, and they can be considered as promising ultrawide-bandgap semiconductors. Finally, the anisotropy in Young's modulus and X-ray diffraction (XRD) patterns of 2−7H BN polymorphs are also investigated in this work.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

BN Polymorphs in Hexagonal 2–7 Stacking Orders: First-Principles and High-Throughput Study

Fan,

Zhao,

Zhao

et al. 2023

Crystal Growth & Design

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“…It was first synthesized from c-B4N4 by Wentorf et al using high temperatures and pressure. It has excellent thermal conductivity and is considered a natural protective coating and a UV emitter. , The metastable phase stacking sequence w-B2N2 occurs in the formation of a covalent bond between B and N atoms with sp 3 and sp 2 hybridization. It is created from h-B2N2 by applying high pressure at ambient temperature. − However, relatively few attempts have been made to address the thermal conductivity, Raman signature, and optical properties, and there have been no predictions of the X-ray absorption near-edge structure (XANES) spectra.…”

Section: Introductionmentioning

confidence: 99%

“…It has excellent thermal conductivity and is considered a natural protective coating and a UV emitter. 30,31 The metastable phase stacking sequence w-B2N2 occurs in the formation of a covalent bond between B and N atoms with sp 3 and sp 2 hybridization. It is created from h-B2N2 by applying high pressure at ambient temperature.…”

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First-Principles Calculations to Investigate the Structural, Electronic, Optical, and Elastic Constants; Thermal Conductivity; Raman Scattering; Mulliken Population; and XPS Loss Features of Boron Nitride Polytypes

Zhang,

Jiao,

S. K. S

et al. 2023

J. Phys. Chem. C

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We systematically studied the structural properties, energetics, charge density, electronic structure, optical properties, hardness, elastic anisotropy properties, mechanical properties, lattice dynamics, thermodynamics, thermal conductivity, Raman scattering, Mulliken population, and core-level X-ray photoelectron spectroscopic (XPS) loss features of boron nitride polytypes and implemented CAmbridge Serial Total Energy Package (CASTEP) code for first-principles calculations based on density functional theory (DFT) along with generalized gradient approximation (GGA) with Perdew−Burke−Ernzerhof (GGA-PBE) exchangecorrelation potential. Our findings on structural parameters agree strongly with the experimental values, with an average error of less than 1%. The acoustic Debye temperature of the boron nitride (BN) polytype is about 1680 K for h-B2N2, 1877 K for c-B4N4, and 1880 K for w-B2N2. The specific heat capacities of h-B2N2, w-B2N2, and c-B4N4 are about 9.437, 7.895, and 3.91 J/(mol K) at 300 K, respectively. To identify significant features and understand the sensitivity of BN polytypes, we estimate that the thermal conductivities for h-B2N2, w-B2N2, and c-B4N4 are 3.905, 10.156, and 22.038 W/(m K) at 300 K, respectively. The elastic constants state that the BN polytypes are mechanically stable and h-B2N2 has a strong anisotropy. The electronic structures reveal that w-B2N2 has a direct band gap of 5.232 eV, while h-B2N2 and c-B4N4 are wide-and indirect-band-gap semiconductors with band gaps of 4.329 and 4.530 eV, respectively. The maximum absorption coefficients in the investigated energy range are 538.50 and 513.66 cm −1 for c-B4N4 and w-B2N2, respectively. The spectra of the K-edge (1s) of the B and N sites have a sharp π* and a broader σ* in the energy region between 5 and 50 eV. These results indicate that BN is a promising material for heat dissipation and has a lot of potential in the development of novel microelectronic devices because of their low density, exceptional strength, high flexibility and stretchability, good thermal stability, and excellent impermeability.

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