论文标题
Ab2x4中的高度可调频带反转（a = ge，sn，pb; b = as，sb，bi; x = se，te）化合物
Highly Tunable Band Inversion in AB2X4 (A=Ge, Sn, Pb; B=As, Sb, Bi; X=Se, Te) Compounds
论文作者
论文摘要
到目前为止，拓扑材料在很大程度上是通过在晶体学数据库中搜索现有化合物而发现的，但是可能有一些新的拓扑材料具有所需的特征，但尚未合成。理想的特征之一是带有很小的直接带隙的频带反转产生的高可调节性，可以通过压力或应变变化来调整以诱导拓扑相变的变化。使用密度函数理论（DFT）计算，我们研究了隔层分层的AB2X4系列化合物，其中A =（GE，SN和PB），B =（AS，SB和BI）以及X =（SE和TE）。通过通过这些系列中已经报道的化合物验证DFT热力学稳定性，我们预测了新的稳定SE化合物，这在晶体学数据库中找不到。其中，我们发现GEBI2SE4和GESB2SE4在Z点具有很小的直接带隙非常接近强拓制绝缘体，可以通过中等压力来调节以诱导频带倒置。重要的是，小型直接带隙的拓扑特征在动量和能量窗口中都很好地孤立，这为研究拓扑相变提供了高可调性。
Topological materials have been discovered so far largely by searching for existing compounds in crystallographic databases, but there are potentially new topological materials with desirable features that have not been synthesized. One of the desirable features is high tunability resulted from the band inversion with a very small direct band gap, which can be tuned by changes in pressure or strain to induce a topological phase transition. Using density functional theory (DFT) calculations, we have studied the septuple layered AB2X4 series compounds, where A=(Ge, Sn and Pb), B=(As, Sb and Bi) and X=(Se and Te). With the DFT thermodynamic stability validated by the already reported compounds in these series, we predict new stable Se compounds, which are not found in crystallographic database. Among them, we find that GeBi2Se4 and GeSb2Se4 having a small direct band gap at the Z point are very close to a strong topological insulator, which can be tuned by a moderate pressure to induce the band inversion. Importantly, the topological features with the small direct band gap are well isolated in both momentum and energy windows, which offers high tunability for studying the topological phase transition.
