Gate-Tunable Phonon Magnetic Moment in Bilayer Graphene
Xiaowei Zhang, Yafei Ren, Chong Wang, Ting Cao, Di Xiao
Abstract
We develop a first-principles quantum scheme to calculate the phonon magnetic moment in solids. As a showcase example, we apply our method to study gated bilayer graphene, a material with strong covalent bonds. According to the classical theory based on the Born effective charge, the phonon magnetic moment in this system should vanish, yet our quantum mechanical calculations find significant phonon magnetic moments. Furthermore, the magnetic moment is highly tunable by changing the gate voltage. Our results firmly establish the necessity of the quantum mechanical treatment, and identify small-gap covalent materials as a promising platform for studying tunable phonon magnetic moment.
Topics & Concepts
Condensed matter physicsMagnetic momentPhononBilayer grapheneElectron magnetic dipole momentGrapheneNeutron magnetic momentMoment (physics)PhysicsSpin magnetic momentProton magnetic momentMaterials scienceQuantum mechanicsMagnetic fieldMagnetic dipoleGraphene research and applicationsTopological Materials and PhenomenaQuantum and electron transport phenomena