Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene
Name
s41467-017-00824-w.pdf
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1.2 MB
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Checksum (MD5)
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Author(s)
Li, J. I. A.
Zibrov, A. A.
Wang, L.
Taniguchi, T.
Watanabe, K.
Hone, J.
Dean, C. R.
Zaletel, M.
Hunt, Benjamin
Ashoori, Raymond
Date Issued
October 2017
Journal
Nature Communications
Publisher
Nature Publishing Group
Citation
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)
Version
Final published version
Abstract
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.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Creative Commons Attribution 4.0 International License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1038/S41467-017-00824-W
