Discovering Electron-Transfer-Driven Changes in Chemical Bonding in Lead Chalcogenides (PbX, where X = Te, Se, S, O)
Discovering Electron-Transfer-Driven Changes in Chemical Bonding in Lead Chalcogenides (PbX, where X = Te, Se, S, O)
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DOI：
10.1002/adma.202005533
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发表时间：
2020-11-02
影响因子：
29.4
通讯作者：
Wuttig, Matthias
中科院分区：
文献类型：
--
作者：
Maier, Stefan;Steinberg, Simon;Wuttig, Matthias
了解固体中化学键的性质对于理解给定化合物的物理和化学性质至关重要。为了探索铅硫族化合物（PbX，其中X = Te，Se，S，O）中化学键合的变化，应用了性质，键断裂和量子力学键合描述符的组合。探索的结果揭示了从PbX（X = Te，Se，S）中的间价键到β-PbO中的离子共价键的电子转移驱动的转变。间价键的特征在于相邻原子通过共享大约一个电子（ES近似为1）和小的电子转移（ET）而保持在一起。从间价键到离子共价键的转变本身表现在这些量子力学描述符（ES和ET）以及基于性质的描述符（即，Born有效电荷（Z*）、介电函数ω（ω）、有效配位数（ECoN）和模式特异性Gruneisen参数（γ（TO），以及键断裂描述符。如果在离子核（ET）和/或原子间区域（ES）发生显著的电荷局部化，则间价键合崩溃。主要改变电子转移的程度打开了定制材料性质的可能性，例如化学键（Z*）和电子（π（无穷大））极化率、光学带隙和以π（2）（ω）为特征的光学带间跃迁。因此，从这项研究中获得的见解突出了金属键合概念的技术相关性及其在材料设计中的潜力。
Understanding the nature of chemical bonding in solids is crucial to comprehend the physical and chemical properties of a given compound. To explore changes in chemical bonding in lead chalcogenides (PbX, where X = Te, Se, S, O), a combination of property-, bond-breaking-, and quantum-mechanical bonding descriptors are applied. The outcome of the explorations reveals an electron-transfer-driven transition from metavalent bonding in PbX (X = Te, Se, S) to iono-covalent bonding in beta-PbO. Metavalent bonding is characterized by adjacent atoms being held together by sharing about a single electron (ES approximate to 1) and small electron transfer (ET). The transition from metavalent to iono-covalent bonding manifests itself in clear changes in these quantum-mechanical descriptors (ES and ET), as well as in property-based descriptors (i.e., Born effective charge (Z*), dielectric function epsilon(omega), effective coordination number (ECoN), and mode-specific Gruneisen parameter (gamma(TO))), and in bond-breaking descriptors. Metavalent bonding collapses if significant charge localization occurs at the ion cores (ET) and/or in the interatomic region (ES). Predominantly changing the degree of electron transfer opens possibilities to tailor material properties such as the chemical bond (Z*) and electronic (epsilon(infinity)) polarizability, optical bandgap, and optical interband transitions characterized by epsilon(2)(omega). Hence, the insights gained from this study highlight the technological relevance of the concept of metavalent bonding and its potential for materials design.