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Effect of Hydrostatic Pressure on Lone Pair Activity and Phonon Transport in Bi2O2S
ACS Applied Energy Materials ( IF 5.4 ) Pub Date : 2023-02-08 , DOI: 10.1021/acsaem.2c03725
N. Yedukondalu 1, 2 , Tribhuwan Pandey 3 , S. C. Rakesh Roshan 4, 5
Affiliation  

Dibismuth dioxychalcogenides, Bi2O2Ch (Ch = S, Se, Te), are a promising class of materials for next-generation electronics and thermoelectrics due to their ultrahigh carrier mobility and excellent air stability. An interesting member of this family is Bi2O2S, which has a stereochemically active 6s2 lone pair of Bi3+ cations, heterogeneous bonding, and a high mass contrast between its constituent elements. In the present study, we have used first-principles calculations in combination with Boltzmann transport theory to systematically investigate the effect of hydrostatic pressure on lattice dynamics and phonon transport properties of Bi2O2S. We found that the ambient Pnmn phase has a low average lattice thermal conductivity (κl) of 1.71 W/(m K) at 300 K. We also predicted that Bi2O2S undergoes a structural phase transition from a low-symmetry (Pnmn) to a high-symmetry (I4/mmm) structure at around 4 GPa due to centering of Bi3+ cations with pressure. Upon compression, the lone pair activity of Bi3+ cations is suppressed, which increases κl by almost 3 times to 4.92 W/(m K) at 5 GPa for the I4/mmm phase. The computed phonon lifetimes and Grüneisen parameters show that anharmonicity decreases with increasing pressure due to further suppression of the lone pair activity and strengthening of intra- and intermolecular interactions, leading to an average room-temperature κl of 12.82 W/(m K) at 20 GPa. Overall, this study provides a comprehensive understanding of the effect of hydrostatic pressure on the stereochemical activity of the lone pair of Bi3+ cations and its implications on the phonon transport properties of Bi2O2S.

中文翻译:

静水压力对 Bi2O2S 中孤对活性和声子传输的影响

二氧硫族化物 Bi 2 O 2 Ch(Ch = S、Se、Te)由于其超高的载流子迁移率和出色的空气稳定性,是一类很有前途的下一代电子产品和热电材料。这个家族中一个有趣的成员是 Bi 2 O 2 S,它具有立体化学活性的 6s 2孤对 Bi 3+阳离子、异质键合以及其组成元素之间的高质量对比。在本研究中,我们利用第一性原理计算结合玻尔兹曼输运理论,系统地研究了静水压力对Bi 2 O 2 晶格动力学和声子输运性质影响S. 我们发现环境Pnmn相在 300 K 时具有 1.71 W/(m K) 的低平均晶格热导率 (κ l )。我们还预测 Bi 2 O 2 S 经历了从低-由于 Bi 3+阳离子在压力下居中,在 4 GPa 左右对称性 ( Pnmn ) 到高对称性 ( I 4/ mmm ) 结构。压缩后,Bi 3+阳离子的孤对活性受到抑制,对于I 4 / mmm ,这将 κ l增加了近 3 倍,在 5 GPa 时达到 4.92 W/(m K)阶段。计算出的声子寿命和 Grüneisen 参数表明,由于孤对活性的进一步抑制和分子内和分子间相互作用的加强,非谐性随着压力的增加而降低,导致平均室温 κ l 为 12.82 W /(m K) 20 吉帕。总的来说,这项研究全面了解静水压力对孤对 Bi 3+阳离子的立体化学活性的影响及其对 Bi 2 O 2 S的声子传输特性的影响。
更新日期:2023-02-08
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