Regensburg 2025 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 4: Topological Insulators
TT 4.5: Talk
Monday, March 17, 2025, 10:30–10:45, H33
Multiplicative Chern insulators — •Archi Banerjee1,2 and Ashley M. Cook1,2 — 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 2Max Planck Institute for the Chemical Physics of Solids, Dresden, Germany
Extending on the previous work on multiplicative topological phases, here we study bulk-boundary correspondence and response signatures of multiplicative Chern insulators (MCIs). Constructing the MCI Bloch Hamiltonian as a symmetry-protected tensor product of two topologically non-trivial parent Chern insulators (CIs), we study 2D MCIs and introduce 3D MCIs, constructed by requiring the two 2D parent Hamiltonians share only one momentum component, rather than both as in the case of the 2D MCI. We study the robustness of bulk-boundary correspondence against bulk perturbations breaking the tensor product structure of the child Hamiltonian, and find the bulk-boundary correspondence remains gapless and evolves to that of a topological skyrmion phase in cases considered here. We also study the response of the 2D MCI to time reversal symmetric flux insertion through two spatially-separated locations in the lattice. We observe a 4π periodic Aharonov-Bohm (AB) effect in which unpaired Majorana zero-modes and associated spin angular momentum are transferred between these two locations. We interpret the AB effect from the perspective of the effective field theories of the quantum skyrmion Hall effect as corresponding to a generalised ν=1/2 FQHE.
Keywords: Multiplicative; Chern Insulator; Aharanov Bohm; Tensor product structure; Charge pumping