Physica status solidi / B 258(1), 2000060 (2020). doi:10.1002/pssb.202000060 special issue: "Special Issue: Topological Insulators: Materials – Fundamental Properties – Devices / Edited by Oliver Rader, Gustav Bihlmayer, Saskia F. Fischer" Physica status solidi / B Basic research 258(1), 2000060 (2021). doi:10.1002/pssb.202000060