Intervalley Scattering of Interlayer Excitons in a MoS$_2$/MoSe$_2$/MoS$_2$ Heterostructure in High Magnetic Field

Alessandro Surrente, Lukasz Klopotowski, Nan Zhang, Michal Baranowski, Anatolie A. Mitioglu, Mariana V. Ballottin, Peter C. M. Christianen, Dumitru Dumcenco, Yen-Cheng Kung, Duncan K. Maude, Andras Kis, Paulina Plochocka

Published 2018-05-25Version 1

Degenerate extrema in the energy dispersion of charge carriers in solids, also referred to as valleys, can be regarded as a binary quantum degree of freedom, which can potentially be used to implement valleytronic concepts in van der Waals heterostructures based on transition metal dichalcogenides. Using magneto-photoluminescence spectroscopy, we achieve a deeper insight into the valley polarization and depolarization mechanisms of interlayer excitons formed across a MoS$_2$/MoSe$_2$/MoS$_2$ heterostructure. We account for the non-trivial behavior of the valley polarization as a function of the magnetic field by considering the interplay between exchange interaction and phonon mediated intervalley scattering in a system consisting of Zeeman-split energy levels. Our results represent a crucial step towards the understanding of the properties of interlayer excitons, with strong implications for the implementation of atomically thin valleytronic devices.