Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster Session I
HL 13.7: Poster
Montag, 12. März 2018, 17:30–19:30, Poster B
Valley polarization dynamics of interlayer excitons in dichalcogenide heterostructures in high magnetic fields — •Johannes Holler1, Jonas Zipfel1, Mariana Ballotin2, Anatolie Mitioglu2, Michael Kempf1, Philipp Nagler1, Fabian Mooshammer1, Alexey Chernikov1, Peter Christianen2, Christian Schüller1, and Tobias Korn1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Germany — 2High Field Magnet Laboratory (HFML EMFL), Radboud University Nijmegen, Netherlands
In the recent years, research on two-dimensional materials has been a rapidly expanding field. Among these materials, a promising class are the transition-metal dichalcogenides (TMDCs). Besides very interesting physics of monolayers, such as spin-valley locking, these TMDCs can be combined to heterostructures, revealing new excitonic properties.
Here, we study MoSe2-WSe2 heterostructures, which create a staggered band alignment so that optically excited electron-hole pairs are spatially separated, leading to the formation of interlayer excitons (IEXs). In magnetic fields of up to 30 Tesla, we observe a giant valley-selective splitting in low-temperature photoluminescence measurements and a resulting near-unity valley polarization. Furthermore, we probe the valley dynamics of the IEX in dependence of the magnetic field. We are able to observe the build-up of the valley polarization after unpolarized excitation, revealing different dynamics and lifetimes for the different valleys.