Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene
The high magnetic field electronic structure of bilayer graphene is enhanced by the spin, valley isospin, and an accidental orbital degeneracy, leading to a complex phase diagram of broken symmetry states. Here, we present a technique for measuring the layer-resolved charge density, from which we di...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
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Nature Publishing Group
2018
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| Online Access: | http://hdl.handle.net/1721.1/114671 https://orcid.org/0000-0001-5031-1673 |
| _version_ | 1826190584165957632 |
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| author | Li, J. I. A. Zibrov, A. A. Wang, L. Taniguchi, T. Watanabe, K. Hone, J. Dean, C. R. Zaletel, M. Hunt, Benjamin Ashoori, Raymond Young, Andrea |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Li, J. I. A. Zibrov, A. A. Wang, L. Taniguchi, T. Watanabe, K. Hone, J. Dean, C. R. Zaletel, M. Hunt, Benjamin Ashoori, Raymond Young, Andrea |
| author_sort | Li, J. I. A. |
| collection | MIT |
| description | The high magnetic field electronic structure of bilayer graphene is enhanced by the spin, valley isospin, and an accidental orbital degeneracy, leading to a complex phase diagram of broken symmetry states. Here, we present a technique for measuring the layer-resolved charge density, from which we directly determine the valley and orbital polarization within the zero energy Landau level. Layer polarization evolves in discrete steps across 32 electric field-tuned phase transitions between states of different valley, spin, and orbital order, including previously unobserved orbitally polarized states stabilized by skew interlayer hopping. We fit our data to a model that captures both single-particle and interaction-induced anisotropies, providing a complete picture of this correlated electron system. The resulting roadmap to symmetry breaking paves the way for deterministic engineering of fractional quantum Hall states, while our layer-resolved technique is readily extendable to other two-dimensional materials where layer polarization maps to the valley or spin quantum numbers. |
| first_indexed | 2024-09-23T08:42:14Z |
| format | Article |
| id | mit-1721.1/114671 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T08:42:14Z |
| publishDate | 2018 |
| publisher | Nature Publishing Group |
| record_format | dspace |
| spelling | mit-1721.1/1146712022-09-23T13:59:54Z Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene Li, J. I. A. Zibrov, A. A. Wang, L. Taniguchi, T. Watanabe, K. Hone, J. Dean, C. R. Zaletel, M. Hunt, Benjamin Ashoori, Raymond Young, Andrea Massachusetts Institute of Technology. Department of Physics Hunt, Benjamin Ashoori, Raymond Young, Andrea The high magnetic field electronic structure of bilayer graphene is enhanced by the spin, valley isospin, and an accidental orbital degeneracy, leading to a complex phase diagram of broken symmetry states. Here, we present a technique for measuring the layer-resolved charge density, from which we directly determine the valley and orbital polarization within the zero energy Landau level. Layer polarization evolves in discrete steps across 32 electric field-tuned phase transitions between states of different valley, spin, and orbital order, including previously unobserved orbitally polarized states stabilized by skew interlayer hopping. We fit our data to a model that captures both single-particle and interaction-induced anisotropies, providing a complete picture of this correlated electron system. The resulting roadmap to symmetry breaking paves the way for deterministic engineering of fractional quantum Hall states, while our layer-resolved technique is readily extendable to other two-dimensional materials where layer polarization maps to the valley or spin quantum numbers. United States. Department of Energy. Office of Basic Energy Sciences (Contract FG02-08ER46514) Gordon and Betty Moore Foundation (Grant GBMF2931) 2018-04-12T17:08:16Z 2018-04-12T17:08:16Z 2017-10 2017-05 2018-04-09T22:04:00Z Article http://purl.org/eprint/type/JournalArticle 2041-1723 http://hdl.handle.net/1721.1/114671 Hunt, B. M. et al. “Direct Measurement of Discrete Valley and Orbital Quantum Numbers in Bilayer Graphene.” Nature Communications 8, 1 (October 2017): 948 © 2017 The Author(s) https://orcid.org/0000-0001-5031-1673 http://dx.doi.org/10.1038/S41467-017-00824-W Nature Communications Creative Commons Attribution 4.0 International License http://creativecommons.org/licenses/by/4.0/ application/pdf Nature Publishing Group Nature |
| spellingShingle | Li, J. I. A. Zibrov, A. A. Wang, L. Taniguchi, T. Watanabe, K. Hone, J. Dean, C. R. Zaletel, M. Hunt, Benjamin Ashoori, Raymond Young, Andrea Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene |
| title | Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene |
| title_full | Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene |
| title_fullStr | Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene |
| title_full_unstemmed | Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene |
| title_short | Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene |
| title_sort | direct measurement of discrete valley and orbital quantum numbers in bilayer graphene |
| url | http://hdl.handle.net/1721.1/114671 https://orcid.org/0000-0001-5031-1673 |
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