Berlin 2018 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 28: 2D materials: Chalcogenides II (joint session HL/DS)
DS 28.11: Vortrag
Donnerstag, 15. März 2018, 12:15–12:30, A 151
Giant magnetic splitting inducing near-unity valley polarization in van der Waals heterostructures — •Philipp Nagler1, Mariana V. Ballottin2, Anatolie A. Mitioglu2, Fabian Mooshammer1, Johannes Holler1, Jonas Zipfel1, Michael Kempf1, Nicola Paradiso1, Christoph Strunk1, Rupert Huber1, Alexey Chernikov1, Peter C. M. Christianen2, Christian Schüller1, and Tobias Korn1 — 1Department of Physics, University of Regensburg, Regensburg, Germany — 2High Field Magnet Laboratory (HFML), Radboud University, The Netherlands
Atomically thin van der Waals heterostructures enable solid-state systems in the ultimate thickness limit. Type II band alignment of transition metal dichalcogenides (TMDCs) leads to the formation of interlayer excitons, which stem from spatially separated electron-hole pairs. These species are highly promising for future valleytronic devices since they combine ultra-long lifetimes with the peculiar spin-valley physics of the constitutent monolayers. Here, we demonstrate strong magnetic coupling of interlayer excitons in a WSe2/MoSe2 heterostructure to an external magnetic field up to 30 T. The observed g factor of -15 by far exceeds typical values of the g factor in TMDC monolayers and enables near-unity valley polarization of long-lived interlayer excitons at high fields. Our findings can be made plausible by taking into account the AB-stacking configuration of the heterostructure where K+ and K− valleys align in momentum space, leading to spin-allowed inter-valley optical transitions.