Dresden 2020 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 21: 2D Materials II: Electronic Structure, Excitations, etc. (joint session O/CPP/HL)

HL 21.10: Talk

Monday, March 16, 2020, 17:30–17:45, WIL C107

Electronic and optical properties of two-dimensional magnets (CrI₃) and their effects on adjacent material (WSe₂/CrI₃) — •Marie-Christin Heißenbüttel, Michael Rohlfing, and Peter Krüger — Institut für Festkörpertheorie WWU, Münster, Deutschland

For the development of novel opto-electronic devices the access and manipulation of the spin degree of freedom is of fundamental importance. The recently discovered 2D magnets provide a great opportunity to study the delicate interplay of spin, orbital, charge and lattice degree of freedom and the manipulation of other non-magnetic 2D materials, as for example TMDCs, by proximity effects. In this talk I will demonstrate our results from ab-initio calculations for the magnetic monolayer of chromium triiodide (CrI₃). The electronic and optical properties are analyzed as well as the effects of magnetism on the optics of WSe₂ within the heterobilayer tungsten diselenide (WSe₂) on CrI₃ are shown. The investigation of CrI₃ by many body perturbation theory (MBPT) within the LDA+GdW approximation reveals a ferromagnetic and insulating behavior and the optical absorption obtained from the solution of the BSE shows large exciton binding energies up to 1.04 eV. Furthermore due to the impact of ferromagnetic proximity effects on the TMDC WSe₂ in the heterosystem WSe₂ / CrI₃ a lifting of the energy degeneracy in the K-valleys of WSe₂ is found. Both the electronic band gap at ±K as well as the corresponding excitons in WSe₂ are affected.