| Autor: |
Erkensten D; Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden. daniel.erkensten@chalmers.se., Brem S; Department of Physics, Philipps-Universität Marburg, 35037 Marburg, Germany., Perea-Causín R; Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden. daniel.erkensten@chalmers.se., Hagel J; Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden. daniel.erkensten@chalmers.se., Tagarelli F; Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.; Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland., Lopriore E; Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.; Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland., Kis A; Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.; Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland., Malic E; Department of Physics, Philipps-Universität Marburg, 35037 Marburg, Germany.; Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden. daniel.erkensten@chalmers.se. |
| Abstrakt: |
Transition-metal dichalcogenide bilayers exhibit a rich exciton landscape including layer-hybridized excitons, i.e. excitons which are of partly intra- and interlayer nature. In this work, we study hybrid exciton-exciton interactions in naturally stacked WSe 2 homobilayers. In these materials, the exciton landscape is electrically tunable such that the low-energy states can be rendered more or less interlayer-like depending on the strength of the external electric field. Based on a microscopic and material-specific many-particle theory, we reveal two intriguing interaction regimes: a low-dipole regime at small electric fields and a high-dipole regime at larger fields, involving interactions between hybrid excitons with a substantially different intra- and interlayer composition in the two regimes. While the low-dipole regime is characterized by weak inter-excitonic interactions between intralayer-like excitons, the high-dipole regime involves mostly interlayer-like excitons which display a strong dipole-dipole repulsion and give rise to large spectral blue-shifts and a highly anomalous diffusion. Overall, our microscopic study sheds light on the remarkable electrical tunability of hybrid exciton-exciton interactions in atomically thin semiconductors and can guide future experimental studies in this growing field of research. |
