论文标题
来自有效轴向场晶体的无间隙标准
Gapless Criterion for Crystals from Effective Axion Field
论文作者
论文摘要
可以有效地确定晶体是否无间隙的无间隙标准对于识别拓扑半学特别有用。在这项工作中，我们基于静态轴向场的批量平均值的简化表达式提出了三维非相互作用晶体的足够无间隙标准。简短的逻辑是，两个不同的简化表达式在绝缘子中给出了相同的值，因此可以通过它们的不匹配来检测无间隙相。我们证明了无间隙标准在具有空间群体26和13的磁系统中的有效性，其中镜子，滑行和反转对称性提供了简化的表达式。特别是，无间隙标准可以识别出对称表示方法所遗漏的无间隙阶段，如太空集团26所示。我们的建议是未来发现拓扑半学的指导原则。
Gapless criteria that can efficiently determine whether a crystal is gapless or not are particularly useful for identifying topological semimetals. In this work, we propose a sufficient gapless criterion for three-dimensional non-interacting crystals, based on the simplified expressions for the bulk average value of the static axion field. The brief logic is that two different simplified expressions give the same value in an insulator, and thus the gapless phase can be detected by the mismatch of them. We demonstrate the effectiveness of the gapless criterion in the magnetic systems with space groups 26 and 13, where mirror, glide, and inversion symmetries provide the simplified expressions. In particular, the gapless criterion can identify gapless phases that are missed by the symmetry representation approach, as illustrated by space group 26. Our proposal serves as a guiding principle for future discovery of topological semimetals.
