Valley-Dependent Interlayer Excitons in Magnetic WSe<sub>2</sub>/CrI<sub>3</sub>
Marie-Christin Heißenbüttel, Thorsten Deilmann, Péter Krüger, Michael Rohlfing
Abstract
Heterostructures of two-dimensional transition-metal dichalcogenides and ferromagnetic substrates are important candidates for the development of viable new spin- or valleytronic devices. For the prototypical bilayer of WSe2 on top of a ferromagnetic layer of CrI3, we find substantially different coupling of both WSe2 K-valleys to the sublayer. Besides an energy splitting of a few meV, the corresponding excitons have significantly different interlayer character with charge transfer allowed at the K̅– point but forbidden at K̅+. The different exciton wave functions result in a distinctly different response to magnetic fields with g factors of about −4.4 and −4.0, respectively. By means of ab initio GW/Bethe-Salpeter equation calculations, these findings establish g factors as tool for investigating the exciton character and shedding light on the detailed quantum-mechanical interplay of magnetic and optical properties which are essential for the targeted development of optoelectronic devices.