Seebeck Coefficient and Electrical Resistivity of Single Crystal B<sub>12</sub>As<sub>2</sub>at High Temperatures

Frye, Clint D.; Edgar, James H.; Ohkubo, I.; Mori, Takao

doi:10.7566/jpsj.82.095001

Cited by 11 publications

(10 citation statements)

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“…We note that the representation of the atomic configuration of t-B 50 N 2 has still not been decisive due to a variety of ways for individual boron and nitrogen atoms to fully and/or partially occupy 13 14 15 16 at.% N different interstitial sites [70][71][72]. In the present work, the atomic configuration of t-B 50 N 2 , recently proposed by Uemura et al [72] is chosen, as it is found to be the lowest-energy configuration, among several considered possible occupations of the interstitial atoms.…”

Section: Resultsmentioning

confidence: 99%

“…As for the three-dimensional bulk crystals, in particular icosahedral boron-rich solids, governed by the three-center two-electron chemical bonds, they exhibit several outstanding properties, such as high chemical stability, high hardness, high melting point, and low wear coefficient [6][7][8][9][10][11][12][13]. Together with the small atomic mass of boron and low density of the compounds, they are thus promising materials for a wide range of technological applications [6,[13][14][15][16][17][18][19][20][21]. For this reason, icosahedral boron-rich solids have become attractive to researchers and have been extensively studied both experimentally and theoretically over the past decades.…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic stability and properties of boron subnitrides from first principles

2017

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We use the first-principles approach to clarify the thermodynamic stability as a function of pressure and temperature of three different α-rhombohedral-boron-like boron subnitrides, with the compositions of B 6 N, B 13 N 2 , and B 38 N 6 , proposed in the literature. We find that, out of these subnitrides with the structural units of B 12 (N-N), B 12 (NBN), and [B 12 (N − N)] 0.33 [B 12 (NBN)] 0.67 , respectively, only B 38 N 6 , represented by [B 12 (N − N)] 0.33 [B 12 (NBN)] 0.67 , is thermodynamically stable. Beyond a pressure of about 7.5 GPa depending on the temperature, also B 38 N 6 becomes unstable, and decomposes into cubic boron nitride and α-tetragonalboron-like boron subnitride B 50 N 2 . The thermodynamic stability of boron subnitrides and relevant competing phases is determined by the Gibbs free energy, in which the contributions from the lattice vibrations and the configurational disorder are obtained within the quasiharmonic and the mean-field approximations, respectively. We calculate lattice parameters, elastic constants, phonon and electronic density of states, and demonstrate that [B 12 (N − N)] 0.33 [B 12 (NBN)] 0.67 is both mechanically and dynamically stable, and is an electrical semiconductor. The simulated x-ray powder-diffraction pattern as well as the calculated lattice parameters of [B 12 (N − N)] 0.33 [B 12 (NBN)] 0.67 are found to be in good agreement with those of the experimentally synthesized boron subnitrides reported in the literature, verifying that B 38 N 6 is the stable composition of α-rhombohedral-boron-like boron subnitride.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermodynamic stability and properties of boron subnitrides from first principles

2017

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“…Such properties thus make the materials promising for a wide range of technological applications, for instance light weight armor, wear-resistant devices, cutting tools [20][21][22][23][24][25], candidates for high temperature electronic [6,26,27] and thermoelectric devices [1,6,[28][29][30], etc. In addition, due to a large thermal neutron absorption cross section of the isotope 10 B, icosahedral boron-rich solids can be used as neutron absorbing materials in nuclear reactors [6,20,31,32].…”

Section: Motivationmentioning

confidence: 99%

“…Furthermore, due to their self-healing property resistant to structural damage, when subjected to high-energy electron radiation, B 12 As 2 and B 12 P 2 are candidates for radiation resistant applications [91,92], including beta-voltaic devices [93]. Recently, B 12 As 2 has been suggested as a candidate for thermoelectric applications at high temperature [29,30]. Since B 12 As 2 and B 12 P 2 are isostructural and isovalent, it would perhaps be possible for them to form alloys with limited change in their electronic properties.…”

Section: Boron Subarsenide and Subphosphidementioning

confidence: 99%

“…Compared to the other icosahedral boron-rich solids, in particular boron carbide, having been frequently addressed in the literature [1,6,17,20,25,27,28,30,35,36,84,91,[94][95][96][108][109][110][111][112][113][114], relatively few studies have so far been made on boron subnitride [19,[115][116][117][118][119][120]. For this reason, several issues about boron subnitride, for example its stable compositions, properties, as well as the correct representation of its basic structural unit, are still inconclusive.…”

Section: Boron Subnitridementioning

confidence: 99%

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Disordered Icosahedral Boron-Rich Solids: A Theoretical Study of Thermodynamic Stability and Properties

Ektarawong¹

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The cover page illustrates the crystal structure of disordered boron carbide (B 4 C), projected on the (100) r crystal plane in rhombohedral symmetry.The cover image is visualized by the VESTA package. Red and white spheres represent boron and carbon atoms, respectively.During the course of research underlying this thesis, Annop Ektarawong was enrolled in Agora Materiae, a multidisciplinary doctoral program at Linköping University, Sweden.c Annop Ektarawong Printed by LiU-Tryck 2017 AbstractThis thesis is a theoretical study of configurational disorder in icosahedral boronrich solids, in particular boron carbide, including also the development of a methodological framework for treating configurational disorder in such materials, namely superatom-special quasirandom structure (SA-SQS). In terms of its practical implementations, the SA-SQS method is demonstrated to be capable of efficiently modeling configurational disorder in icosahedral boron-rich solids, whiles the thermodynamic stability as well as the properties of the configurationally disordered icosahedral boron-rich solids, modeled from the SA-SQS method, can be directly investigated, using the density functional theory (DFT).In case of boron carbide, especially B 4 C and B 13 C 2 compositions, the SA-SQS method is used for modeling configurational disorder, arising from a high concentration of low-energy B/C substitutional defects. The results, obtained from the DFT-based calculations, demonstrate that configurational disorder of B and C atoms in boron carbide is not only thermodynamically favored at high temperature, but it also plays an important role in altering the properties of boron carbide − for example, restoration of higher rhombohedral symmetry of B 4 C, a metal-tononmetal transition and a drastic increase in the elastic moduli of B 13 C 2 . The configurational disorder can also explain large discrepancies, regarding the properties of boron carbide, between experiments and previous theoretical calculations, having been a long standing controversial issue in the field of icosahedral boronrich solids, as the calculated properties of the disordered boron carbides are found to be in qualitatively good agreement with those, observed in experiments. In order to investigate the configurational evolution of B 4 C as a function of temperature, beyond the SA-SQS level, a brute-force cluster-expansion method in combination with Monte Carlo simulations is implemented. The results demonstrate that configurational disorder in B 4 C indeed essentially takes place within the icosahedra in a way that justifies the focus on low-energy defect patterns of the superatom picture.The investigation of the thermodynamic stability of icosahedral carbon-rich iii iv boron carbides beyond the believed solubility limit of carbon (20 at.% C) demonstrates that, apart from B 4 C generally addressed in the literature, B 2.5 C represented by B 10 C p 2 (CC) is predicted to be thermodynamically stable with respect to B 4 C as well as pure boron and carbon under high pressure...

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Perspectives of High-Temperature Thermoelectric Applications and p-type and n-type Aluminoborides

Mori

2016

JOM

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Seebeck Coefficient and Electrical Resistivity of Single Crystal B₁₂As₂at High Temperatures

Cited by 11 publications

References 19 publications

Thermodynamic stability and properties of boron subnitrides from first principles

Thermodynamic stability and properties of boron subnitrides from first principles

Disordered Icosahedral Boron-Rich Solids: A Theoretical Study of Thermodynamic Stability and Properties

Perspectives of High-Temperature Thermoelectric Applications and p-type and n-type Aluminoborides

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Seebeck Coefficient and Electrical Resistivity of Single Crystal B12As2at High Temperatures

Cited by 11 publications

References 19 publications

Thermodynamic stability and properties of boron subnitrides from first principles

Thermodynamic stability and properties of boron subnitrides from first principles

Disordered Icosahedral Boron-Rich Solids: A Theoretical Study of Thermodynamic Stability and Properties

Perspectives of High-Temperature Thermoelectric Applications and p-type and n-type Aluminoborides

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Seebeck Coefficient and Electrical Resistivity of Single Crystal B₁₂As₂at High Temperatures