Weak-Field Hall Resistivity and Spin-Valley Flavor Symmetry Breaking in Magic-Angle Twisted Bilayer Graphene
Ming Xie, A. H. MacDonald
Abstract
Near a magic twist angle, the lowest energy conduction and valence bands of bilayer graphene moiré superlattices become extremely narrow. The band dispersion that remains is sensitive to the moiré's strain pattern, nonlocal tunneling between layers, and filling-factor-dependent Hartree and exchange band renormalizations. In this Letter, we analyze the influence of these band-structure details on the pattern of flavor symmetry breaking observed in this narrow band system and on the associated pattern of Fermi surface reconstructions revealed by weak-field Hall and Shubnikov-de Haas magnetotransport measurements.
Topics & Concepts
Condensed matter physicsBilayer grapheneSuperlatticeSymmetry breakingMaterials scienceGrapheneTwistBilayerQuantum tunnellingElectrical resistivity and conductivityElectronic band structureHall effectFermi energyFermi levelFermi surfaceQuantum Hall effectBand gapSymmetry (geometry)PhysicsHartreeValence (chemistry)Thermal conductionQuasi Fermi levelSemimetalDispersion relationConduction bandMagnetoresistanceDispersion (optics)Graphene research and applicationsTopological Materials and Phenomena2D Materials and Applications