Twisted bilayer graphene (TBG) with interlayer twist angles near the magic angle ≈1.08∘ hosts flat bands and exhibits correlated states including Mott-like insulators, superconductivity and magnetism. Here we report combined temperature-dependent transport measurements of the longitudinal and Hall resistivities in close to magic-angle TBG. While the observed longitudinal resistivity follows linear temperature T dependence consistent with previous reports, the Hall resistance shows an anomalous T dependence with the cotangent of the Hall angle cot ΘH∝T2. Boltzmann theory for quasiparticle transport predicts that both the resistivity and cot ΘH should have the same T dependence, contradicting the observed behavior. This failure of quasiparticle-based theories is reminiscent of other correlated strange metals such as cuprates.
@article{arxiv.2008.06907,
title = {Strange metal behavior of the Hall angle in twisted bilayer graphene},
author = {Rui Lyu and Zachary Tuchfeld and Nishchhal Verma and Haidong Tian and Kenji Watanabe and Takashi Taniguchi and Chun Ning Lau and Mohit Randeria and Marc Bockrath},
journal= {arXiv preprint arXiv:2008.06907},
year = {2021}
}