Zhang Xiuwen, Liu Qihang, Xu Qiunan, Dai Xi, Zunger Alex
Shenzhen Key Laboratory of Flexible Memory Materials and Devices, College of Electronic Science and Technology , Shenzhen University , Guangdong 518060 , China.
Renewable and Sustainable Energy Institute , University of Colorado , Boulder , Colorado 80309 , United States.
J Am Chem Soc. 2018 Oct 24;140(42):13687-13694. doi: 10.1021/jacs.8b06652. Epub 2018 Oct 15.
Intriguing physical properties of materials stem from their chemical constituents, whereas the connection between them is often not clear. Here, we uncover a general chemical classification for the two quantum phases in the honeycomb ABX structure-topological insulator (TI) and topological Dirac semimetal (TDSM). First, we find among the 816 (existing as well as hypothetical) calculated compounds, 160 TIs (none were noted before), 96 TDSMs, 282 normal insulators (NIs), and 278 metals. Second, based on this classification, we have distilled a simple chemical regularity based on compound formulas for the selectivity between TI and TDSM: the ABX compounds that are TDSM have B atoms (part of the BX honeycomb layers) that come from the periodic table columns XI (Cu, Ag, Au) or XII (Zn, Cd, Hg), or Mg (group II), whereas the ABX compounds whose B atoms come from columns I (Li, Na, K, Rb, Cs) or II (Ca, Sr, Ba) are TIs. Third, focusing on the ABX bismide compounds that are thermodynamically stable, we find a structural motif that delivers topological insulation and stability at the same time. This study opens the way to simultaneously design new topological materials based on the compositional rules indicated here.
材料有趣的物理性质源于其化学成分，然而它们之间的联系往往并不清晰。在此，我们揭示了蜂窝状ABX结构中的两种量子相——拓扑绝缘体（TI）和拓扑狄拉克半金属（TDSM）的通用化学分类。首先，我们在816种（包括已有的和假设的）计算化合物中发现，有160种TI（之前未被提及）、96种TDSM、282种正常绝缘体（NI）和278种金属。其次，基于这种分类，我们根据化合物分子式提炼出了一种关于TI和TDSM选择性的简单化学规律：属于TDSM的ABX化合物中，B原子（BX蜂窝层的一部分）来自元素周期表第XI族（铜、银、金）或第XII族（锌、镉、汞），或镁（第II族），而B原子来自第I族（锂、钠、钾、铷、铯）或第II族（钙、锶、钡）的ABX化合物则是TI。第三，聚焦于热力学稳定的ABX铋化合物，我们发现了一种能同时实现拓扑绝缘和稳定性的结构基序。这项研究为基于此处所示的组成规则同时设计新型拓扑材料开辟了道路。
