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HL: Fachverband Halbleiterphysik
HL 9: 2D Materials and Heterostructures: Interlayer Excitons
HL 9.13: Talk
Monday, March 18, 2024, 18:15–18:30, EW 201
Theoretical description of ultraviolet interlayer trions in bilayer 2H-WSe2 — •Ruven Hübner1, Alexander Steinhoff1, and Matthias Florian2 — 1Institut für Theoretische Physik, Universität Bremen, Germany — 2University of Michigan, Dept. of Electrical Engineering and Computer Science, Ann Arbor, MI, USA
For an extended period, interlayer excitons in bilayers of transition metal dichalcogenides (TMDs) have received a great deal of attention. Numerous studies have explored the influence of material combination, stacking configuration, twist angle and external electric fields. However, most such studies exclusively focus on excitons, formed near the band edge, confined to electronic states with a parabolic dispersion and a homogeneous interlayer character. More recently, experimental findings have unveiled ultraviolet excitons, involving high-lying and non-parabolic bands of TMD materials at approximately double the band gap energy [1]. These states open up the possibility of forming new kinds of trions, in which the additional charge carrier is provided by doping electrons near the band edge. In this talk we focus on such high-lying trions formed within a WSe2 inversion symmetric homobilayer. We develop a theoretic framework, which classifies distinct trion species based on their dominant interlayer localization of each of the three constituent particles, starting from Wannierized electronic states based on a DFT calculation. We discuss the influence of doping density and use our results to explain very recent experiments.
[1] KQ. Lin et al., Nature Communications 12, 5500 (2021)
Keywords: exciton; trion; bilayer; interlayer; inversion symmetry