Regensburg 2022 – scientific programme
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DS: Fachverband Dünne Schichten
DS 7: 2D Materials 2 (joint session HL/CPP/DS)
DS 7.12: Talk
Monday, September 5, 2022, 18:15–18:30, H36
Strain control of spins in monolayer WSe2 — •Abhijeet Kumar1, Douglas J. Bock1, Pablo Hernández López2, Sebastian Heeg2, Christoph Schattauer3, Florian Libisch3, Bianca Höfer1, Cornelius Gahl1, and Kirill I. Bolotin1 — 1Freie Universität Berlin, Arnimalle 14, 14195, Berlin, Germany — 2Institut für Physik und IRIS Adlershof, Humboldt Universität zu Berlin, 12489 Berlin, Germany — 3Vienna University of Technology, Austria
Mechanical strain controls band hierarchy and excitons in the transition metal dichalcogenides (TMDs). Here, we apply remarkably large biaxial strain exceeding 2% in a suspended 1L-WSe2 at cryogenic temperatures and unveil novel strain responses. First, the conduction bands hybridize with the in-gap localized defects under 1% strain that breaks spin-valley locking. Second, we show that the defects are critical for valley physics as we observe near 100% loss of exciton valley coherence under hybridization. At the same time, the associated defects and dark states gain up to 400% valley polarization. Finally, we show ultrafast strain control of spins and charges in a suspended WSe2 device. Our observations may play a critical role in the applications of TMDs in strain-valleytronics.