Miniband engineering and topological phase transitions in topological-insulator–normal-insulator superlattices

Periodic stacking of topologically trivial and non-trivial layers with opposite symmetry the valence conduction bands induces topological interface states that, in strong coupling limit, hybridize both across normal insulator layers. Using band structure engineering, such superlattices can be effectively realized using IV-VI lead tin chalcogenides. This leads to emergent minibands a tunable topology as demonstrated by theory experiments. The are proven magneto-optical spectroscopy, revealing Landau level transitions at center edges artificial superlattice mini Brillouin zone. Their character is identified phase within observed function temperature. critical temperature this transition well miniband gap width precisely controlled layer thicknesses compositions. witnesses generation new fully quasi-3D state that provides template for realization magnetic Weyl semimetals other strongly interacting phases.