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| Main Authors: | , , |
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| Format: | Preprint |
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2023
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2311.17859 |
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| _version_ | 1866910658510979072 |
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| author | Lei, Chao Mahon, Perry T. MacDonald, Allan H. |
| author_facet | Lei, Chao Mahon, Perry T. MacDonald, Allan H. |
| contents | The electronic ground state of a three-dimensional (3D) band insulator with time-reversal ($Θ$) symmetry or time-reversal times a discrete translation ($ΘT_{1/2}$) symmetry is classified by a $\mathbb{Z}_{2}$-valued topological invariant and characterized by quantized magnetoelectric response. Here we demonstrate by explicit calculation in model $\mathbb{Z}_{2}$ topological insulator thin-films that whereas the magnetoelectric response is localized at the surface in the $Θ$ symmetry (nonmagnetic) case, it is nonuniversally partitioned between surface and interior contributions in the $ΘT_{1/2}$ (antiferromagnetic) case, while remaining quantized. Within our model the magnetic field induced polarization arises entirely from an anomalous $\mathscr{N}=0$ Landau level subspace within which the projected Hamiltonian is a generalized Su-Schrieffer-Heeger model whose topological properties are consistent with those of the starting 3D model. We identify a new connection between the ground-state geometry of that 3D model and surface-interior partitioning in thin films. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2311_17859 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Bulk versus surface: Nonuniversal partitioning of the topological magnetoelectric effect Lei, Chao Mahon, Perry T. MacDonald, Allan H. Mesoscale and Nanoscale Physics Quantum Gases The electronic ground state of a three-dimensional (3D) band insulator with time-reversal ($Θ$) symmetry or time-reversal times a discrete translation ($ΘT_{1/2}$) symmetry is classified by a $\mathbb{Z}_{2}$-valued topological invariant and characterized by quantized magnetoelectric response. Here we demonstrate by explicit calculation in model $\mathbb{Z}_{2}$ topological insulator thin-films that whereas the magnetoelectric response is localized at the surface in the $Θ$ symmetry (nonmagnetic) case, it is nonuniversally partitioned between surface and interior contributions in the $ΘT_{1/2}$ (antiferromagnetic) case, while remaining quantized. Within our model the magnetic field induced polarization arises entirely from an anomalous $\mathscr{N}=0$ Landau level subspace within which the projected Hamiltonian is a generalized Su-Schrieffer-Heeger model whose topological properties are consistent with those of the starting 3D model. We identify a new connection between the ground-state geometry of that 3D model and surface-interior partitioning in thin films. |
| title | Bulk versus surface: Nonuniversal partitioning of the topological magnetoelectric effect |
| topic | Mesoscale and Nanoscale Physics Quantum Gases |
| url | https://arxiv.org/abs/2311.17859 |