First-principles electron-phonon interactions and electronic transport in large-angle twisted bilayer graphene
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1.
California Institute of Technology
Abstract
Twisted bilayer graphene (tBLG) has emerged as an exciting platform for novel condensed matter physics. However, electron-phonon (𝑒-ph) interactions in tBLG and their effects on electronic transport are not completely understood. Here we show first-principles calculations of 𝑒-ph interactions and resistivity in commensurate tBLG with large twist angles of 13.2 and 21.8 degrees. These calculations overcome key technical barriers, including large unit cells of up to 76 atoms, Brillouin-zone folding of the 𝑒-ph interactions, and unstable lattice vibrations due to the AA-stacked domains. We show that 𝑒-ph interactions due to layer-breathing phonons enhance intervalley scattering in large-angle tBLG. This interaction effectively couples the two layers, which are otherwise electronically decoupled at such large twist angles. As a result, the phonon-limited resistivity in tBLG deviates from the temperature-linear trend characteristic of monolayer graphene and tBLG near the magic angle. Taken together, our work quantifies 𝑒-ph interactions and scattering mechanisms in tBLG, revealing subtle interlayer coupling effects at large twist angles.
Copyright and License
© 2024 American Physical Society.
Acknowledgement
This work was primarily supported by the National Science Foundation under Grant No. OAC-2209262. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility using NERSC award DDR-ERCAP0026831.
Data Availability
information about the band structure of large-angle tBLG, carrier scattering rates in MLG, phonon dispersions in tBLG at different temperatures, resistivity of 21.8 degree tBLG beyond the relaxation time approximation, scaling of the e-ph matrix elements with unit cell size, interlayer versus intralayer e-ph coupling in 21.8 degree tBLG, resistivity in 21.8 degree tBLG for different doping levels, and Eliashberg function and e-ph coupling constant in large-angle tBLG.
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Additional details
- National Science Foundation
- OAC-2209262
- United States Department of Energy
- DDR-ERCAP0026831