The investigation of excitons in van-der-Waals heterostructures has led to profound insights into the interplay of crystal symmetries and fundamental effects of light-matter coupling. In particular, the polarization selection rules in undistorted, slightly twisted heterostructures of MoSe2/WSe2 were found to be connected with the Moir\'e superlattice. Here, we report the emergence of a significant degree of circular polarization of excitons in such a hetero-structure upon non-resonant driving with a linearly polarized laser. The effect is present at zero magnetic field, and sensibly reacts on perpendicularly applied magnetic field. The giant magnitude of polarization, which cannot be explained by conventional birefringence or optical activity of the twisted lattice, suggests a kinematic origin arising from an emergent pyromagnetic symmetry in our structure, which we exploit to gain insight into the microscopic processes of our device.
@article{arxiv.2105.09948,
title = {Intrinsic circularly-polarized exciton emission in a twisted van-der-Waals heterostructure},
author = {J. Michl and S. A. Tarasenko and F. Lohof and G. Gies and M. von Helversen and R. Sailus and S. Tongay and T. Taniguchi and K. Watanabe and T. Heindel and S. Reitzenstein and T. Shubina and S. Höfling and C. Antón-Solanas and C. Schneider},
journal= {arXiv preprint arXiv:2105.09948},
year = {2022}
}
Comments
Main text: 8 pages, 3 figures. Supplementary: 2 pages