Fig. 2: Material candidates of wallpaper fermion and third-order topological insulators.
From: Third-order topological insulators with wallpaper fermions in Tl4PbTe3 and Tl4SnTe3
a Top and b side views of Tl4XTe3 (X = Pb/Sn) conventional unit cell. c Numbers of occupied bands with positive (P) and negative (N) parities at eight \({\Bbb T}\)-invariant momenta (Λα) with SOC. d Brillouin zone for the primitive unit cell of Tl4XTe3, and projected 2D (001) Brillouin zone. e–h Bulk band structures of e, g, Tl4PbTe3 and f, h, Tl4SnTe3 e, f, without and g, h with SOC. The bands are orbitally weighted with the contribution of Te-pz and X/Tl-pz states. The Fermi level is indicated with a dashed line.
