In 2017, Professor Xu Gang discovered and proposed a special three-dimensional honeycomb model, which can realize a variety of topological states such as ideal Weyl semi-metal, three-dimensional topological insulator, and node line semi-metal. Combined with the first-principles calculation, it is found that the electronic structures of the LnSI (Ln=Lu, Y and Gd) series of materials fully conform to the above model and have corresponding non-trivial topological states. Among them, LuSI and YSI are three-dimensional topological insulators, and GdSI is an ideal Weyl semi-metal with only two Weyl nodes. At present, GdSI has attracted a lot of interest from many experimental groups, providing an ideal platform for the research of Weyl physics.
Simin Nie, Gang Xu, Fritz B. Prinz, and Shou-cheng Zhang. PNAS 114 (40): 10596-10600 (2017)
Paper link:Topological semimetal in honeycomb lattice LnSI
