Floating Edge Bands in the Bernevig-Hughes-Zhang model with Altermagnetism

Abstract

Floating edge bands (FEB) have been identified in systems such as obstructed atomic insulators and layered nonsymmorphic semimetals, attracting considerable interest recently. Here we demonstrate that FEB can arise in a simplified model incorporating altermagnetism. By enhancing the Bernevig-Hughes-Zhang model on a square lattice with additional altermagnetic and Zeeman fields perpendicular to the 2D plane, we uncover the emergence of FEB that are distinct from the bulk bands across the entire Brillouin zone and over broad parameter regimes. We calculate topological phase diagrams, highlighting the strong topological properties characterized by the Chern number and the weak topological properties marked by the winding number. Furthermore, we provide analytical results of the energy spectrum and the wave functions of the FEB. We also study the robustness of the FEB, showcasing its resilience against various perturbations such as geometric rotation, energy spectrum asymmetry, and spin coupling. Our findings advance our understanding of FEB and may pave new avenues for further exploration of topological phases in quantum materials.

arXiv comment13 pages, 8 figures

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Cited by in corpus (8)

• Interplay of Altermagnetic Order and Wilson Mass in the Dirac Equation: Helical Edge States without Time-Reversal Symmetry
• Model Hamiltonian for Altermagnetic Topological Insulators
• Altermagnetism and its induced higher-order topology on the Lieb lattice
• Non-Hermitian higher-order topological insulators enabled by altermagnet engineering
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• Josephson effects in the spin-triplet superconductor/altermagnet/spin-triplet superconductor junctions: the detection of the intrinsic $\mathbf{d}$-vector
• Exactly solvable spin liquids in Kitaev bilayers and moiré superlattices