Tunable phase transitions from semimetals to Chern insulators in two-dimensional quadratic-band-crossing materials
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866910255747694592 |
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| author | Bian, Wen-Hao Wang, Jing |
| author_facet | Bian, Wen-Hao Wang, Jing |
| contents | We systematically investigate how static symmetry-breaking perturbations and dynamic Floquet terms via a polarized light manipulate the topological phase transitions in the two-dimensional quadratic-band-crossing-point (QBCP) materials. The Berry curvature shows distinct behavior in such two situations. It is linearly and quadratically proportional to the product of microstructural parameters $t_{x,z}$ for the former and the latter, respectively. The static perturbation eliminates the QBCP and opens an energy gap, which leads to the momentum-inversion symmetry of Berry curvature. This yields a nontrivial Chern number determined by the microstructural parameters. In contrast, we demonstrate that either a circularly or an elliptically polarized light breaks the time-reversal symmetry, transforming the QBCP semimetal into a Chern insulator with a quantized anomalous Hall conductivity $σ_{xy} = Ce^2/\hbar$, where the Chern number is governed by the polarization angle. Moreover, the linear polarization preserves the central antisymmetry of the Berry curvature, giving rise to a topological trivial insulator. These results establish a tunable topological phase transition from a QBCP semimetal to Chern insulator in the two-dimensional QBCP materials. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2506_19378 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Tunable phase transitions from semimetals to Chern insulators in two-dimensional quadratic-band-crossing materials Bian, Wen-Hao Wang, Jing Mesoscale and Nanoscale Physics Strongly Correlated Electrons We systematically investigate how static symmetry-breaking perturbations and dynamic Floquet terms via a polarized light manipulate the topological phase transitions in the two-dimensional quadratic-band-crossing-point (QBCP) materials. The Berry curvature shows distinct behavior in such two situations. It is linearly and quadratically proportional to the product of microstructural parameters $t_{x,z}$ for the former and the latter, respectively. The static perturbation eliminates the QBCP and opens an energy gap, which leads to the momentum-inversion symmetry of Berry curvature. This yields a nontrivial Chern number determined by the microstructural parameters. In contrast, we demonstrate that either a circularly or an elliptically polarized light breaks the time-reversal symmetry, transforming the QBCP semimetal into a Chern insulator with a quantized anomalous Hall conductivity $σ_{xy} = Ce^2/\hbar$, where the Chern number is governed by the polarization angle. Moreover, the linear polarization preserves the central antisymmetry of the Berry curvature, giving rise to a topological trivial insulator. These results establish a tunable topological phase transition from a QBCP semimetal to Chern insulator in the two-dimensional QBCP materials. |
| title | Tunable phase transitions from semimetals to Chern insulators in two-dimensional quadratic-band-crossing materials |
| topic | Mesoscale and Nanoscale Physics Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2506.19378 |