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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.