Strange metal behavior of the Hall angle in twisted bilayer graphene

Twisted bilayer graphene (TBG) with interlayer twist angles near the magic angle $\approx 1.08^{\circ}$ hosts flat bands and exhibits correlated states including Mott-like insulators, superconductivity magnetism. Here we report combined temperature-dependent transport measurements of longitudinal Hall resistivities in close to magic-angle TBG. While observed resistivity follows linear temperature $T$ dependence consistent previous reports, resistance shows an anomalous cotangent cot $\Theta{_H} \propto T^2$. Boltzmann theory for quasiparticle predicts that both $\Theta{_H}$ should have same dependence, contradicting behavior. This failure quasiparticle-based theories is reminiscent other strange metals such as cuprates.