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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2511.02446 |
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| _version_ | 1866914481176576000 |
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| author | Wang, Binbin Hu, Jiayuan Fu, Bo Li, Jiaqi Kong, Yunchuan Bai, Kai-Zhi Shen, Shun-Qing Xiao, Di |
| author_facet | Wang, Binbin Hu, Jiayuan Fu, Bo Li, Jiaqi Kong, Yunchuan Bai, Kai-Zhi Shen, Shun-Qing Xiao, Di |
| contents | The interplay between topological materials and local symmetry breaking gives rise to diverse topological quantum phenomena. A notable example is the parity anomalous semimetal (PAS), which hosts a single unpaired gapless Dirac cone with a half-integer quantized Hall conductivity. Here, we realize this phase in a magnetic topological sandwich structure by applying an in-plane magnetic field. This configuration aligns the magnetization of one surface in-plane while preserving magnetization out-of-plane on the opposite surface, satisfying the condition for a gapless surface state near the Fermi level on only one surface. Our key evidence is a distinctive two-stage evolution of the conductivity tensor ($σ_{xy}$, $σ_{xx}$). The first stage culminates in the PAS at the fixed point ($\frac{e^2}{2h}$, $m \frac{e^2}{h}$), where $m \approx 0.6$ corresponds to the minimal longitudinal conductivity of a single gapless Dirac cone of fermions on a 2D lattice. This PAS state remains stabilized and is superposed with a gapped band flow in the second stage. This observation demonstrates that this state stabilized by the in-plane field resists localization--contrary to conventional expectations for 2D electron systems with broken time reversal symmetry. The dynamic transition from an integer quantized insulator to a half-integer quantized semimetal establishes this material system as a versatile platform for exploring parity anomaly physics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_02446 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Parity Anomalous Semimetal with Minimal Conductivity Induced by an In-Plane Magnetic Field Wang, Binbin Hu, Jiayuan Fu, Bo Li, Jiaqi Kong, Yunchuan Bai, Kai-Zhi Shen, Shun-Qing Xiao, Di Materials Science Mesoscale and Nanoscale Physics The interplay between topological materials and local symmetry breaking gives rise to diverse topological quantum phenomena. A notable example is the parity anomalous semimetal (PAS), which hosts a single unpaired gapless Dirac cone with a half-integer quantized Hall conductivity. Here, we realize this phase in a magnetic topological sandwich structure by applying an in-plane magnetic field. This configuration aligns the magnetization of one surface in-plane while preserving magnetization out-of-plane on the opposite surface, satisfying the condition for a gapless surface state near the Fermi level on only one surface. Our key evidence is a distinctive two-stage evolution of the conductivity tensor ($σ_{xy}$, $σ_{xx}$). The first stage culminates in the PAS at the fixed point ($\frac{e^2}{2h}$, $m \frac{e^2}{h}$), where $m \approx 0.6$ corresponds to the minimal longitudinal conductivity of a single gapless Dirac cone of fermions on a 2D lattice. This PAS state remains stabilized and is superposed with a gapped band flow in the second stage. This observation demonstrates that this state stabilized by the in-plane field resists localization--contrary to conventional expectations for 2D electron systems with broken time reversal symmetry. The dynamic transition from an integer quantized insulator to a half-integer quantized semimetal establishes this material system as a versatile platform for exploring parity anomaly physics. |
| title | Parity Anomalous Semimetal with Minimal Conductivity Induced by an In-Plane Magnetic Field |
| topic | Materials Science Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2511.02446 |