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

• Applicants: Professor Dr. Arthur Ernst; Privatdozent Dr. Jürgen Henk
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2013 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 237597403

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.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1666: Topological Insulators: Materials - Fundamental Properties - Devices
• Co-Investigator: Professorin Dr. Ingrid Mertig