Lattice collective modes from a continuum model of magic-angle twisted bilayer graphene
Ajesh Kumar, Ming Xie, A. H. MacDonald
Abstract
Utilizing a time-dependent mean-field approximation, the authors calculate collective particle-hole modes in a correlated insulating phase of magic-angle twisted bilayer graphene. They find that the low-energy modes are well described by a model with a local pseudospin composed of spin, valley, and orbital degrees of freedom in each moir\'e unit cell. They further show that the intra-flavor collective mode couples strongly to terahertz light, giving a significant signature in the system's optical response.
Topics & Concepts
Bilayer grapheneCondensed matter physicsMagic angleLattice (music)GraphenePhysicsTheoretical physicsQuantum mechanicsSpectral lineAcousticsGraphene research and applicationsTopological Materials and PhenomenaMechanical and Optical Resonators