Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 4: 2D Materials and their Heterostructures I (joint session DS/HL)

HL 4.7: Talk

Monday, March 17, 2025, 16:45–17:00, H3

Effect of spin-dependent tunneling in a MoSe₂/Cr₂Ge₂Te₆ van der Waals heterostructure on exciton and trion emission — •Annika Bergmann¹, Swarup Deb^1,2, Veronika Schneidt¹, Mustafa Hemaid¹, Kenji Watanabe³, Takashi Taniguchi⁴, Rico Schwartz¹, and Tobias Korn¹ — ¹Institute of Physics, Rostock University, Rostock, Germany — ²Saha Institute of Nuclear Physics, Kolkata, India — ³Research Center for Electronic and Optical Materials, Tsukuba, Japan — ⁴Research Center for Materials Nanoarchitectonics, Tsukuba, Japan

In recent years, thin films of magnetic van der Waals materials have gained increasing interest due to their potential applications in spintronics. For instance, heterostructures (HS) consisting of ferromagnetic CRI₃ and a WSe₂ monolayer have demonstrated the existence of magnetic proximity effects, manifesting in the lifting of WSe₂ valley degeneracy as well as helicity-dependent photoluminescence (PL) emission of the WSe₂ monolayer in proximity to the 2D ferromagnet [1,2]. Here, we study HS consisting of monolayer MoSe₂ and few-layer ferromagnetic Cr₂Ge₂Te₆ (CGT). Under circularly polarized excitation, PL measurements show that the MoSe₂ exciton-trion emission ratio depends on the relative orientation of excitation helicity and CGT magnetization, even though the PL emission itself is unpolarized. This hints at an ultrafast, spin-dependent interlayer charge transfer that competes with exciton and trion formation and recombination.

[1] D. Zhong et al., Science Advances, 3 (2017)

[2] D. Zhong et al., Nat. Nanotechnol. 15 (2020)

Keywords: Van der Waals Heterostructures; 2D Ferromagnets; Optical Spectroscopy; Interlayer Charge Transfer