M. Trushin, Goerbig, M. O., and Belzig, W., “Model Prediction of Self-Rotating Excitons in Two-Dimensional Transition-Metal Dichalcogenides”, PHYSICAL REVIEW LETTERS, vol. 120, p. 187401, 2018.Abstract
Using the quasiclassical concept of Berry curvature we demonstrate that a Dirac exciton-a pair of Dirac quasiparticles bound by Coulomb interactions-inevitably possesses an intrinsic angular momentum making the exciton effectively self-rotating. The model is applied to excitons in two-dimensional transition metal dichalcogenides, in which the charge carriers are known to be described by a Dirac-like Hamiltonian. We show that the topological self-rotation strongly modifies the exciton spectrum and, as a consequence, resolves the puzzle of the overestimated two-dimensional polarizability employed to fit earlier spectroscopic measurements.