Physical Review B publishes the latest research results of Prof. Xu Nan of the Institute for Advanced Study online in the form of an Artical titled "Inherited weak topological insulator signatures in the topological hourglass semimetal Nb3XTe6"

After restoring the translational symmetry of the system, we focus for the first time on Nb3XTe6(X=Si,Ge) material with the least degree of Si intercalation. We find that Nb3XTe6 possesses bulk band inversion and spin-polarized surface states evolved from a weak topological insulator phase. Considering the self-selected orbital coupling, a multi-node chain consisting of the same pair of valence and conduction bands opens the energy gap.

At the same time, the properties of weak topological insulators appear homologous to hourglass fermions. Unlike previous topological insulators formed based on band inversion without symmetry protection. This unique topological state with a pair of conduction and valence bands simultaneously encodes the properties of a weak topological insulator and an hourglass semimetal, and is protected by non-point symmetry.