Magneto-Induced Topological Phase Transition in Inverted InAs/GaSb Bilayers
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arXiv
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866929642913398784 |
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| author | Han, Zhongdong Li, Tingxin Zhang, Long Du, Rui-Rui |
| author_facet | Han, Zhongdong Li, Tingxin Zhang, Long Du, Rui-Rui |
| contents | We report a magneto-induced topological phase transition in inverted InAs/GaSb bilayers from a quantum spin Hall insulator to a normal insulator. We utilize a dual-gated Corbino device in which the degree of band inversion, or equivalently the electron and hole densities, can be continuously tuned. We observe a topological phase transition around the magnetic field where a band crossing occurs, that is accompanied by a bulk-gap closure characterized by a bulk conductance peak (BCP). In another set of experiments, we study the transition under a tilted magnetic field (tilt angle $θ$). We observe the characteristic magneto-conductance around BCP as a function of $θ$, which dramatically depends on the density of the bilayers. In a relatively deep-inversion (hence a higher density) regime, where the electron-hole hybridization dominates the excitonic interaction, the BCP grows with $θ$. On the contrary, in a shallowly-inverted (a lower density) regime, where the excitonic interaction dominates the hybridization, the BCP is suppressed indicating a smooth crossover without a gap closure. This suggests the existence of a low-density, correlated insulator with spontaneous symmetry breaking near the critical point. Our highly controllable electron-hole system offers an ideal platform to study interacting topological states as proposed by recent theories. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_04830 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Magneto-Induced Topological Phase Transition in Inverted InAs/GaSb Bilayers Han, Zhongdong Li, Tingxin Zhang, Long Du, Rui-Rui Mesoscale and Nanoscale Physics We report a magneto-induced topological phase transition in inverted InAs/GaSb bilayers from a quantum spin Hall insulator to a normal insulator. We utilize a dual-gated Corbino device in which the degree of band inversion, or equivalently the electron and hole densities, can be continuously tuned. We observe a topological phase transition around the magnetic field where a band crossing occurs, that is accompanied by a bulk-gap closure characterized by a bulk conductance peak (BCP). In another set of experiments, we study the transition under a tilted magnetic field (tilt angle $θ$). We observe the characteristic magneto-conductance around BCP as a function of $θ$, which dramatically depends on the density of the bilayers. In a relatively deep-inversion (hence a higher density) regime, where the electron-hole hybridization dominates the excitonic interaction, the BCP grows with $θ$. On the contrary, in a shallowly-inverted (a lower density) regime, where the excitonic interaction dominates the hybridization, the BCP is suppressed indicating a smooth crossover without a gap closure. This suggests the existence of a low-density, correlated insulator with spontaneous symmetry breaking near the critical point. Our highly controllable electron-hole system offers an ideal platform to study interacting topological states as proposed by recent theories. |
| title | Magneto-Induced Topological Phase Transition in Inverted InAs/GaSb Bilayers |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2404.04830 |