Derivation of Wannier orbitals and minimal-basis tight-binding Hamiltonians for twisted bilayer graphene: First-principles approach
ORAL
Abstract
The complexity of the atomic-scale structures in twisted bilayer graphene (TBG) has made even the study of single-particle physics at low energies around the Fermi level challenging. We provide a convenient and physically motivated picture of single-particle physics in TBG using reduced models with the smallest possible number of localized orbitals. The reduced models exactly reproduce the low-energy bands of ab initio tight-binding models, including the effects of atomic relaxations. We obtain for the first time the corresponding Wannier orbitals that incorporate all symmetries of TBG, which are also calculated as a function of angle, a requisite first step towards incorporating electron interaction effects. We construct eight-band and five-band models for the low-energy states for twist angles between 1.3° and 0.6°.
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Presenters
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Stephen Carr
Harvard University
Authors
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Stephen Carr
Harvard University
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Shiang Fang
Harvard University, Department of Physics and Astronomy, Rutgers University, Harvard, Department of Physics, Harvard University, Physics, Harvard University
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Hoi Chun Po
Massachusetts Institute of Technology, MIT, Department of Physics, MIT, Department of Physics, Massachusetts Institute of Technology, Massachusetts Institute of Technology MIT
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Ashvin Vishwanath
Harvard University, Physics, Harvard University, Department of Physics, Harvard University
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Efthimios Kaxiras
Harvard University, Department of Physics, Harvard University