Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 40: Poster: Topological Materials

O 40.1: Poster

Tuesday, March 19, 2024, 18:00–20:00, Poster D

Topological phases of quasi-one-dimensional systems — •Nemanja Madić, Tatjana Vuković, and Saša Dmitrović — University of Belgrade Faculty of Physics, Belgrade, Serbia

Obstructed atomic limits (OALs) of crystalline insulators are topological phases characterized by the Wannier orbitals centers unmovable to ion-occupied positions. Complete information on the orbital's movability from the Wyckoff position (WP) is encoded within the symmetry group of the system. The symmetry of a quasi-one-dimensional (Q1D) system is described by one of the line groups gathered within thirteen infinite families. Their electronic structures are always Wannierizable; consequently, all topological insulating phases of such systems correspond to OALs. As inequivalent topological insulating phases are separated by closing the band gap or breaking the crystalline symmetry, the complete set of such phases can be deduced by analyzing the Q1D systems symmetry group. Here, we explore the OALs of spinless and spinful systems whose symmetry groups belong to the 11th and 13th families. To this end, firstly, the real space invariants, needed to test the movability of Wannier centers allocated at the maximal WP of the line groups, are calculated. Next, these results and recently obtained sets of elementary band representations of ordinary and double line groups are applied to obtain the set of distinct Wannier homotopy classes. Finally, district ion positions of the several systems, with equal symmetry groups, are analyzed to identify all possible phases corresponding to the OAL. Results are illustrated on models created within the PythTB package.

Keywords: topological crystalline insulator; obstructed atomic limit; line groups; real space invariants