Tunable and giant valley-selective Hall effect in gapped bilayer graphene
Berry curvature is analogous to magnetic field but in momentum space and is commonly present in materials with nontrivial quantum geometry. It endows Bloch electrons with transverse anomalous velocities to produce Hall-like currents even in the absence of a magnetic field. We report the direct obser...
| Main Authors: | , , , , , , , , |
|---|---|
| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2022
|
| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/162589 |
| _version_ | 1811689539175972864 |
|---|---|
| author | Yin, Jianbo Tan, Cheng Barcons-Ruiz, David Torre, Iacopo Watanabe, Kenji Taniguchi, Takashi Song, Justin Chien Wen Hone, James Koppens, Frank H. L. |
| author2 | School of Physical and Mathematical Sciences |
| author_facet | School of Physical and Mathematical Sciences Yin, Jianbo Tan, Cheng Barcons-Ruiz, David Torre, Iacopo Watanabe, Kenji Taniguchi, Takashi Song, Justin Chien Wen Hone, James Koppens, Frank H. L. |
| author_sort | Yin, Jianbo |
| collection | NTU |
| description | Berry curvature is analogous to magnetic field but in momentum space and is commonly present in materials with nontrivial quantum geometry. It endows Bloch electrons with transverse anomalous velocities to produce Hall-like currents even in the absence of a magnetic field. We report the direct observation of in situ tunable valley-selective Hall effect (VSHE), where inversion symmetry, and thus the geometric phase of electrons, is controllable by an out-of-plane electric field. We use high-quality bilayer graphene with an intrinsic and tunable bandgap, illuminated by circularly polarized midinfrared light, and confirm that the observed Hall voltage arises from an optically induced valley population. Compared with molybdenum disulfide (MoS2), we find orders of magnitude larger VSHE, attributed to the inverse scaling of the Berry curvature with bandgap. By monitoring the valley-selective Hall conductivity, we study the Berry curvature's evolution with bandgap. This in situ manipulation of VSHE paves the way for topological and quantum geometric optoelectronic devices, such as more robust switches and detectors. |
| first_indexed | 2024-10-01T05:49:42Z |
| format | Journal Article |
| id | ntu-10356/162589 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T05:49:42Z |
| publishDate | 2022 |
| record_format | dspace |
| spelling | ntu-10356/1625892023-11-06T15:35:19Z Tunable and giant valley-selective Hall effect in gapped bilayer graphene Yin, Jianbo Tan, Cheng Barcons-Ruiz, David Torre, Iacopo Watanabe, Kenji Taniguchi, Takashi Song, Justin Chien Wen Hone, James Koppens, Frank H. L. School of Physical and Mathematical Sciences Science::Physics Valley-Selective Hall Effect Bilayer Membrane Berry curvature is analogous to magnetic field but in momentum space and is commonly present in materials with nontrivial quantum geometry. It endows Bloch electrons with transverse anomalous velocities to produce Hall-like currents even in the absence of a magnetic field. We report the direct observation of in situ tunable valley-selective Hall effect (VSHE), where inversion symmetry, and thus the geometric phase of electrons, is controllable by an out-of-plane electric field. We use high-quality bilayer graphene with an intrinsic and tunable bandgap, illuminated by circularly polarized midinfrared light, and confirm that the observed Hall voltage arises from an optically induced valley population. Compared with molybdenum disulfide (MoS2), we find orders of magnitude larger VSHE, attributed to the inverse scaling of the Berry curvature with bandgap. By monitoring the valley-selective Hall conductivity, we study the Berry curvature's evolution with bandgap. This in situ manipulation of VSHE paves the way for topological and quantum geometric optoelectronic devices, such as more robust switches and detectors. Ministry of Education (MOE) Nanyang Technological University Submitted/Accepted version This work is supported by European Union’s Horizon 2020 Research and Innovation Programme under grant agreement ref. 881603 (Graphene Flagship Core Project 3) (F.H.L.K.); European Research Council (ERC) TOPONANOP under grant agreement ref. 726001 (F.H.L.K.); the government of Spain [PID2019-106875GB-I00; FJC2018-037098-I; Severo Ochoa CEX2019-000910-S(MCIN/ AEI/10.13039/501100011033)] (F.H.L.K.); Fundació Cellex, Fundació Mir-Puig (F.H.L.K.); Generalitat de Catalunya (CERCA,AGAUR, SGR 1656) (F.H.L.K.); European Union’s Horizon 2020 Programme under the Marie Skłodowska-Curie grant agreements VHPC ref. 747927 (J.Y.); National Natural Science Foundation of China (grant refs. 52072043 and T2188101) (J.Y.); National Key R & D Program of China under grant ref. 2020YFA0308900(J.Y.); National Science Foundation program for Emerging Frontiers in Research and Innovation (EFRI-1741660) (C.T. and J.H.); the Ministry of Education Singapore, under its MOEAcRF Tier 3 Award MOE2018-T3-1-002 (J.C.W.S.); and a Nanyang Technological University start-up grant (NTU-SUG)(J.C.W.S.). 2022-10-31T07:34:27Z 2022-10-31T07:34:27Z 2022 Journal Article Yin, J., Tan, C., Barcons-Ruiz, D., Torre, I., Watanabe, K., Taniguchi, T., Song, J. C. W., Hone, J. & Koppens, F. H. L. (2022). Tunable and giant valley-selective Hall effect in gapped bilayer graphene. Science, 375(6587), 1398-1402. https://dx.doi.org/10.1126/science.abl4266 0036-8075 https://hdl.handle.net/10356/162589 10.1126/science.abl4266 35324299 2-s2.0-85127028058 6587 375 1398 1402 en MOE2018-T3-1-002 Science © 2022 American Association for the Advancement of Science. All rights reserved. This article may be downloaded for personal use only. Any other use requires prior permission of the copyright holder. The Version of Record is available online at http://doi.org/10.1126/science.abl4266. application/pdf |
| spellingShingle | Science::Physics Valley-Selective Hall Effect Bilayer Membrane Yin, Jianbo Tan, Cheng Barcons-Ruiz, David Torre, Iacopo Watanabe, Kenji Taniguchi, Takashi Song, Justin Chien Wen Hone, James Koppens, Frank H. L. Tunable and giant valley-selective Hall effect in gapped bilayer graphene |
| title | Tunable and giant valley-selective Hall effect in gapped bilayer graphene |
| title_full | Tunable and giant valley-selective Hall effect in gapped bilayer graphene |
| title_fullStr | Tunable and giant valley-selective Hall effect in gapped bilayer graphene |
| title_full_unstemmed | Tunable and giant valley-selective Hall effect in gapped bilayer graphene |
| title_short | Tunable and giant valley-selective Hall effect in gapped bilayer graphene |
| title_sort | tunable and giant valley selective hall effect in gapped bilayer graphene |
| topic | Science::Physics Valley-Selective Hall Effect Bilayer Membrane |
| url | https://hdl.handle.net/10356/162589 |
| work_keys_str_mv | AT yinjianbo tunableandgiantvalleyselectivehalleffectingappedbilayergraphene AT tancheng tunableandgiantvalleyselectivehalleffectingappedbilayergraphene AT barconsruizdavid tunableandgiantvalleyselectivehalleffectingappedbilayergraphene AT torreiacopo tunableandgiantvalleyselectivehalleffectingappedbilayergraphene AT watanabekenji tunableandgiantvalleyselectivehalleffectingappedbilayergraphene AT taniguchitakashi tunableandgiantvalleyselectivehalleffectingappedbilayergraphene AT songjustinchienwen tunableandgiantvalleyselectivehalleffectingappedbilayergraphene AT honejames tunableandgiantvalleyselectivehalleffectingappedbilayergraphene AT koppensfrankhl tunableandgiantvalleyselectivehalleffectingappedbilayergraphene |