Topological semimetal phases in HgTe-related alloys: Berryology and surface transport

拓扑非平凡的半金属--Dirac和Weyl半金属--显示出侵入式的性质：在整体上是点状的费米曲面，在Weyl半金属的情况下在表面上是弧形的开费米面。除了HgTe和HgTe-HgTe1-xSx置换合金中已建立的平凡而强烈的拓扑绝缘体相之外，我们还将沿着[001]方向的应变显示拓扑Dirac半金属相和Weyl半金属相，我们将进一步探索拓扑半金属的未知领域：其他类似HgTe和Hgs的材料是否显示出拓扑非平凡半金属相？拓扑非平凡无序系统，特别是替代合金，如何进行拓扑表征？拓扑半金属相如何在表面敏感的传输中表现出来？Weyl半金属独特的表面电子结构，即费米弧的具体特征是什么？此外，我们将继续研究磁性修饰的拓扑绝缘体，以识别表现出量子反常霍尔效应的系统。

Topological nontrivial semimetals - Dirac and Weyl semimetals - show intruiging properties: point-like Fermi surfaces in the bulk and at the surface arc-shaped open Fermi surfaces in the case of Weyl semimetals. Motivated by our prediction that - besides the established trivial and strong topological insulator phases of HgTe and HgS - HgTe1-xSx substitutional alloys show topological Dirac semimetal and Weyl semimetal phases upon strain along the [001] direction we will explore the unchartered territory of topological semimetals further:Do other materials similar to HgTe and HgS exhibit topological nontrivial semimetal phases?How can topological nontrivial disordered systems, in particular substitutional alloys, be topologically characterized?How do topological semimetal phases manifest themselves in surface-sensitive transport? What are specific signatures of the unique surface electronic structures of Weyl semimetals, i.e. the Fermi arcs?Furthermore, we will continue our work on magnetically modified topological insulators, to identify systems that exhibit a quantum anomalous Hall effect.