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DOE OSTI · 2345179

Ground-state order in magic-angle graphene at filling ν = - 3 : A full-scale density matrix renormalization group study

Wang, Tianle·Parker, Daniel E.·Soejima, Tomohiro·Hauschild, Johannes·Anand, Sajant·Bultinck, Nick·Zaletel, Michael P.
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Abstract

Here we investigate twisted bilayer graphene (TBG) at filling ν = -3 in the presence of realistic heterostrain. Strain amplifies the band dispersion and drives the system beyond the strong-coupling regime of previous theoretical studies. We use DMRG to conduct an unbiased, large-scale numerical calculations that include all spin and valley degrees of freedom, up to bond dimension χ = 24576. We establish a global phase diagram that unifies a number of theoretical and experimental results. Near zero strain we find an intervalley-coherent quantized anomalous Hall (QAH-IVC) state, a competitive strong-coupling order that evaded past numerical studies. A tiny strain around 0.05% drives a transition into an incommensurate Kekulé spiral (IKS) phase, supporting the mean-field prediction in [Kwan, Phys. Rev. X 11, 041063 (2021)2160-330810.1103/PhysRevX.11.041063]. Even higher strains above 0.2% favor a flavor-symmetric metallic order, which may explain metals found at ν = -3 in many experiments.

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Wang, Tianle, Parker, Daniel E., Soejima, Tomohiro, Hauschild, Johannes, Anand, Sajant, Bultinck, Nick, Zaletel, Michael P.. 2023-12-08. Ground-state order in magic-angle graphene at filling ν = - 3 : A full-scale density matrix renormalization group study. https://doi.org/10.1103/physrevb.108.235128

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