Alternating twisted mutilayer graphene: generic partition rules, double flat bands, and orbital magnetoelectric effect

Abstract

Twisted graphene systems have draw significant attention due to the discoveries of various correlated and topological phases. In particular, recently the alternating twisted trilayer graphene is discovered to exhibit unconventional superconductivity, which motivates us to study the electronic structures and possible interesting correlation effects of this class of alternating twisted graphene systems. In this work we consider generic alternating twisted multilayer graphene (ATMG) systems with $M$-$L$-$N$ stacking configurations, in which the $M$ ($L$) graphene layers and the $L$ ($N$) layers are twisted by an angle $\theta$ (-$\theta$). Based on analysis from a simplified $\text{k}\cdot \text{p}$ model approach, we analytically derive generic partition rules for the low-energy electronic structures, which exhibit various intriguing band dispersions including one pair of flat bands, two pairs of flat bands, as well as flat bands co-existing with with Dirac cones, quadratic bands, or more generally $E(\mathbf{k})\sim k^J$ dispersions ($J$ is positive integer) for each spin and valley. Such unusual non-interacting electronic structures may have unconventional correlation effects. Especially for a mirror symmetric ATMG system with two pairs of flat bands (per spin per valley), we find that Coulomb interactions may drive the system into a state breaking both time-reversal and mirror symmetries, which can exhibit a novel type of orbital magnetoelectric effect due to the interwining of electric polarization and orbital magnetization orders in the symmetry-breaking state.

References in corpus (8)

• Tunable Phase Boundaries and Ultra-Strong Coupling Superconductivity in Mirror Symmetric Magic-Angle Trilayer Graphene
• Lattice relaxation and energy band modulation in twisted bilayer graphenes
• Band structure and topological property of twisted double bilayer graphenes
• Coulomb screening and thermodynamic measurements in magic-angle twisted trilayer graphene
• Momentum space quantum Monte Carlo on twisted bilayer Graphene
• Correlated insulators, density wave states, and their nonlinear optical response in magic-angle twisted bilayer graphene
• TSTG II: Projected Hartree-Fock Study of Twisted Symmetric Trilayer Graphene
• Current Switching of Valley Polarization in Twisted Bilayer Graphene

Cited by in corpus (7)

• Theory of fractional Chern insulator states in pentalayer graphene moiré superlattice
• Magic-Angle Twisted Symmetric Trilayer Graphene as Topological Heavy Fermion Problem
• Kekulé spirals and charge transfer cascades in twisted symmetric trilayer graphene
• Magic momenta and three dimensional Landau levels from a three dimensional graphite moiré superlattice
• Moiré fractals in twisted graphene layers
• Orbital moiré and quadrupolar triple-q physics in a triangular lattice
• Superpolarized Electron-Hole Liquid and Multiferroicity in Multilayer Graphene