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DOE OSTI · 3682493

Weak localization and universal conductance fluctuations in large-area twisted bilayer graphene

Talkington, Spenser [University of Pennsylvania]·Mallick, Deb [ORNL] (ORCID:000900005806411X)·Chen, Jane [ORNL] (ORCID:0000000203399657)·Mead, Benjamin [University of Pennsylvania]·Yang, Seong-Jun [Pohang University of Science and Technology (POSTECH), Korea]·Kim, Cheol-Joo [Pohang University of Science and Technology (POSTECH), Korea]·Adams, Shaffique [Washington University, St. Louis]·Wu, Liang [University of California, Berkeley]·Brahlek, Matthew [ORNL] (ORCID:0000000329000648)·Mele, Eugene [University of Pennsylvania]
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Abstract

We study diffusive magnetotransport in highly 𝑝-doped large-area twisted bilayer graphene in 1∘, 7∘, 9∘, and 20∘ samples. All samples exhibit weak localization, from which we extract the phase coherence length and intervalley scattering lengths, and from that determine that dephasing is caused by electron-electron scattering and intervalley scattering is caused by point defects. We observe signatures of universal conductance fluctuations in the 9∘ sample, which has high mobility and is near the van Hove singularity. Further improvements in sample quality and applications to large-area moiré materials will open new avenues to observe quantum interference effects.

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Talkington, Spenser [University of Pennsylvania], Mallick, Deb [ORNL] (ORCID:000900005806411X), Chen, Jane [ORNL] (ORCID:0000000203399657), Mead, Benjamin [University of Pennsylvania], Yang, Seong-Jun [Pohang University of Science and Technology (POSTECH), Korea], Kim, Cheol-Joo [Pohang University of Science and Technology (POSTECH), Korea], Adams, Shaffique [Washington University, St. Louis], Wu, Liang [University of California, Berkeley], Brahlek, Matthew [ORNL] (ORCID:0000000329000648), Mele, Eugene [University of Pennsylvania]. 2026-04-01. Weak localization and universal conductance fluctuations in large-area twisted bilayer graphene. https://doi.org/10.1103/xv5t-qvcm

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