Doubling the perovskite cell (double perovskite) has been found to open new possibilities for engineering functional materials, magnetic materials in particular. This route should be applicable to the antiperovskite (aPV) class. In the pnictide based double aPV (2aPV) class introduced here magnetism is very rare, and we address them as new topological materials, possibly with thermoelectric interest. We have found that the 2aPV supercell provides a systematically larger band gap that can serve to inhibit bulk conductivity, and also large spin-orbit coupling (SOC) for band inversion. We present examples from a broad study of double antiperovskites focusing on the X$_6$AA$'$B$_2$ configuration, where X is the alkaline earth element and A and B are the group 5A pnictogens. We find that an ``extended s'' state at the valence band minimum, described alternatively as a cation valence state or a modulated interstitial planewave state, plays a crucial role in both topological and thermoelectric properties. Several of these compounds may house topological phases, while transport calculations indicate they may also find themselves useful in thermoelectric applications.

中文翻译：

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双反钙钛矿pnictides的拓扑和热电特性

已发现双钙钛矿电池（双钙钛矿）为工程功能材料，特别是磁性材料开辟了新的可能性。这条路线应该适用于反钙钛矿（aPV）类。在此处介绍的基于 pnictide 的双 aPV (2aPV) 类中，磁性非常罕见，我们将它们视为新的拓扑材料，可能具有热电兴趣。我们发现 2aPV 超级电池提供了一个系统性更大的带隙，可用于抑制体电导率，以及用于带反转的大自旋轨道耦合 (SOC)。我们展示了双反钙钛矿的广泛研究的例子，重点是 X$_6$AA$'$B$_2$ 配置，其中 X 是碱土元素，A 和 B 是 5A 族致敏原。我们发现价带最小值处的“扩展 s”状态，或者被描述为阳离子价态或调制间隙平面波态，在拓扑和热电特性中起着至关重要的作用。其中一些化合物可能包含拓扑相，而传输计算表明它们也可能在热电应用中有用。