First-Principles investigation of Pressure-Induced structural transformations of barium borates in the BaO-B2O3-BaF2 system in the range of 0–10 GPa

Sagatov, Nursultan E.; Bekker, Tatyana B.; Podborodnikov, Ivan V.; Litasov, Konstantin D.

doi:10.1016/j.commatsci.2021.110735

Cited by 5 publications

(7 citation statements)

References 46 publications

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“…The cell contains four graphite cassettes with holes 0.9 mm diameter and 1.1 mm deep. Based on the results of a numerical study, 23 the pressure value of 3 GPa was chosen. Experiments were carried out by compressing to 3 MN (corresponding to a pressure of 3 GPa) and heating to the desired temperature of 900 °C at a rate of 100 °C/min.…”

Section: ■ Experimental Proceduresmentioning

confidence: 99%

“…11 The outstanding nonlinear optical properties of β-BaB First-principles investigation is an important prerequisite for a search and design of new materials. In our recent work, 23 modification BaB 2 O 4 -Pna2 1 stable above 1.0 GPa and modification BaB 2 O 4 -Pa3̅ stable above 6.1 GPa were discovered as the result of a numerical study of phase stability in the BaO-B 2 O 3 −BaF 2 ternary system. The BaB 2 O 4 -Pna2 1 structure was produced by optimizing the CaB 2 O 4 -Pna2 1 structure.…”

Section: ■ Introductionmentioning

confidence: 99%

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γ-BaB₂O₄: High-Pressure High-Temperature Polymorph of Barium Borate with Edge-Sharing BO₄ Tetrahedra

et al. 2022

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The α- and β-modifications of barium metaborate are important functional materials used in optoelectronic devices. A new theoretically predicted modification of BaB2O4 has been synthesized under conditions of 3 GPa and 900 °C, using the DIA-type apparatus. The new high-pressure modification, γ-BaB2O4, crystallizes in a centrosymmetrical group of monoclinic syngony (P21/n (#14), a = 4.6392(4) Å, b = 10.2532(14) Å, c = 7.066(1) Å, β = 91.363(10)°, Z = 4). A distinctive feature of the γ-BaB2O4 structure is the presence of edge-sharing tetrahedra [B2O6] which form infinite double chains ∞[B4O4O8/2] stretching along the a axis. The number of known structural types with the [B2O6] group is limited. Phase γ-BaB2O4 has the shortest distance between boron atoms of shared tetrahedra among all currently known compounds. The [B2O6] group angles are 95.5° and 105.5°. Thermodynamic stability and electronic properties of the γ-BaB2O4 modification were studied. The width of the band gap, calculated using the HSE06 functional, is 7.045 eV which implies transparency in the deep-UV region. Experimental and numerical methods which demonstrate a good match were used to the study the Raman spectra of γ-BaB2O4 and β-BaB2O4 modifications. In the Raman spectra of γ-BaB2O4, the most intense band at a frequency of 853 cm–1 was found to correspond to the symmetric bending mode of the B–O–B–O ring in edge-sharing tetrahedra.

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Section: ■ Experimental Proceduresmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

γ-BaB₂O₄: High-Pressure High-Temperature Polymorph of Barium Borate with Edge-Sharing BO₄ Tetrahedra

et al. 2022

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“…13 Our recent first-principles study of the stability of phases in the BaO−B 2 O 3 −BaF 2 system at the pressure range of 0−10 GPa has revealed the same phase transitions for barium tetraborate BaB 4 O 7 at 1.8 and 7.5 GPa. 14 One of the main tasks of materials science is to establish the connection between composition, structure, properties, and synthesis conditions. Since the number of experimental methods that make it possible to study the properties of high-pressure phases is limited, mainly due to the small volume of the material obtained, we believe that the study of Raman spectra is of fundamental importance.…”

Section: ■ Introductionmentioning

confidence: 99%

High-Pressure Synthesis, Electronic Properties, and Raman Spectroscopy of Barium Tetraborate BaB₄O₇ Polymorphs

Bekker

Sagatov

Podborodnikov

et al. 2022

Crystal Growth & Design

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The synthesis of high-pressure modification of barium tetraborate β-BaB 4 O 7 has been carried out at 3 GPa and 1000 °C in a DIA-type apparatus. Single-crystal X-ray analysis shows that β-BaB 4 O 7 crystallizes in a centrosymmetric group (Pnam (#62), a = 9.0029(3) Å, b = 4.3006(7) Å, c = 10.9795(8) Å, Z = 4). The density of the β-BaB 4 O 7 phase increases by 22% relative to the ambient-pressure α-BaB 4 O 7 phase. The P−T diagrams for the αand β-BaB 4 O 7 phases have been calculated. The dynamic stability of β-BaB 4 O 7 at ambient pressure was confirmed by the absence of imaginary modes in the phonon spectra. The band gap values obtained using the HSE06 hybrid functional are 6.821 and 8.075 eV for αand β-BaB 4 O 7 phases, respectively, with indirect transitions. The value of 8.075 eV indicates that β-BaB 4 O 7 can transmit to the deep-UV region. For the first time, the Raman spectra of the αand β-BaB 4 O 7 phases have been studied by both experimental and numerical methods. The vasp_raman.py code was used to calculate the polarizability tensors for each crystal mode. The assignment of vibrations of cations, interconnected triangle, and/or tetrahedral groups (BO 3 and BO 4 ) of both modifications was carried out by comparing the experimental and ab initio calculated spectra and the result is in agreement with the interpretation developed for borates, aluminosilicates, and carbonates.

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“…Considering the lower molecular weight of the [BO 3 ] group compared to the [CO 3 ] group, we can assume a lower disordering temperature for borates compared to carbonates. The Ba 3 (BO 3 ) 2 barium orthoborate 18 was chosen as the subject of investigation due to its outstanding structure which is formed by the [Ba 12 (BO 3 ) 6 ] 6+ ''framework'' with channels along the c-axis. The [Ba 12 (BO 3 ) 6 ] 6+ ''framework'' 17,19,20 contains two types of [BO 3 ] groups, which are parallel to and out of the ab-plane.…”

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“…Both cube and anticube cages are filled with statically disordered [BO 3 ] groups. To perform molecular dynamics (MD) simulations, we used the structural model of Ba 3 (BO 3 ) 2 described in our previous work 18 with ordered [BO 3 ] groups in cube and anticube cages (Fig. 1).…”

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Ba₃(BO₃)₂: the first example of dynamic disorder in a borate crystal

Sagatov

Gavryushkin

Bekker

et al. 2022

Phys. Chem. Chem. Phys.

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First-Principles investigation of Pressure-Induced structural transformations of barium borates in the BaO-B2O3-BaF2 system in the range of 0–10 GPa

Cited by 5 publications

References 46 publications

γ-BaB₂O₄: High-Pressure High-Temperature Polymorph of Barium Borate with Edge-Sharing BO₄ Tetrahedra

γ-BaB₂O₄: High-Pressure High-Temperature Polymorph of Barium Borate with Edge-Sharing BO₄ Tetrahedra

High-Pressure Synthesis, Electronic Properties, and Raman Spectroscopy of Barium Tetraborate BaB₄O₇ Polymorphs

Ba₃(BO₃)₂: the first example of dynamic disorder in a borate crystal

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First-Principles investigation of Pressure-Induced structural transformations of barium borates in the BaO-B2O3-BaF2 system in the range of 0–10 GPa

Cited by 5 publications

References 46 publications

γ-BaB2O4: High-Pressure High-Temperature Polymorph of Barium Borate with Edge-Sharing BO4 Tetrahedra

γ-BaB2O4: High-Pressure High-Temperature Polymorph of Barium Borate with Edge-Sharing BO4 Tetrahedra

High-Pressure Synthesis, Electronic Properties, and Raman Spectroscopy of Barium Tetraborate BaB4O7 Polymorphs

Ba3(BO3)2: the first example of dynamic disorder in a borate crystal

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γ-BaB₂O₄: High-Pressure High-Temperature Polymorph of Barium Borate with Edge-Sharing BO₄ Tetrahedra

γ-BaB₂O₄: High-Pressure High-Temperature Polymorph of Barium Borate with Edge-Sharing BO₄ Tetrahedra

High-Pressure Synthesis, Electronic Properties, and Raman Spectroscopy of Barium Tetraborate BaB₄O₇ Polymorphs

Ba₃(BO₃)₂: the first example of dynamic disorder in a borate crystal