Insights into the Charge-Transfer Stabilization of Heterostructure Components with Unstable Bulk Analogs,Chemistry of Materials

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Insights into the Charge-Transfer Stabilization of Heterostructure Components with Unstable Bulk Analogs
Chemistry of Materials ( IF 7.2 ) Pub Date : 2018-06-25 00:00:00 , DOI: 10.1021/acs.chemmater.8b01594
Marco Esters ₁ , Richard G. Hennig ₂ , David C. Johnson ₁

Affiliation

Solid state chemists have yet to find a targeted approach based on simple rules to predict new materials with desired physical properties. Recent advances in computational high-throughput methods have led to the creation of large databases with predicted new compounds. While many of these compounds are unstable, some may be stabilized inside heterostructures. BiSe is an example for such a compound where the rock-salt structure is unstable in bulk but can be found in misfit layer compounds and ferecrystals. In some of these heterostructures, BiSe also exhibits antiphase boundaries (APBs), periodic Bi–Bi pairings that interrupt the alternating pattern of the rock-salt structure. Understanding the behavior of BiSe may aid in the discovery of new heterostructure components where no stable bulk analog exists. We used density functional theory (DFT) and crystal orbital Hamilton populations (COHPs) to explain the different stabilities of rock-salt structured BiSe. COHPs show that rock-salt structured BiSe has occupied antibonding states at the Fermi level, which destabilize the structure. In heterostructures, these states can be depopulated by donating electrons into an adjacent layer or by forming APBs to localize electrons into a Bi–Bi bond. The results suggest that the depopulation of antibonding states is crucial to stabilizing rock-salt structured BiSe, and that BiSe needs to be paired with a suitable electron acceptor. We predict that this is a general principle that can be applied to other compounds with unstable polytypes and suggest that COHPs should play a larger role in the discovery of new heterostructure components.

中文翻译：

不稳定本体模拟对异质结构组分电荷转移稳定的见解

固态化学家尚未找到基于简单规则的有针对性的方法来预测具有所需物理性质的新材料。计算高通量方法的最新进展已导致创建了具有预测的新化合物的大型数据库。尽管这些化合物中的许多不稳定，但有些可能在异质结构内部稳定。BiSe是此类化合物的一个例子，其中盐-盐结构整体上不稳定，但可以在错配层化合物和铁晶体中找到。在其中一些异质结构中，BiSe还表现出反相边界（APB），周期性的Bi-Bi对，从而中断了岩盐结构的交替模式。了解BiSe的行为可能有助于发现不存在稳定的本体类似物的新异质结构组件。我们使用密度泛函理论（DFT）和晶体轨道汉密尔顿族（COHPs）来解释岩盐结构BiSe的不同稳定性。COHPs表明，岩盐结构的BiSe在费米能级上占据了反键状态，这使结构不稳定。在异质结构中，可以通过向相邻层供电子或通过形成APB使电子定位到Bi-Bi键来减少这些状态。结果表明，反键态的减少对于稳定岩盐结构化的BiSe至关重要，BiSe需要与合适的电子受体配对。我们预测这是可应用于具有不稳定多型的其他化合物的一般原理，并建议COHP在发现新的异质结构组分中应发挥更大的作用。

更新日期：2018-06-25

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