Dresden 2020 – scientific programme

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DS: Fachverband Dünne Schichten

DS 4: 2D semiconductors and van der Waals heterostructures I (joint session HL/DS/O)

DS 4.9: Talk

Monday, March 16, 2020, 12:00–12:15, POT 81

Biexcitons in 2D transition metal dichalcogenide from first principle: binding energies and fine structure — •Abderrezak Torche and Gabriel Bester — Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany

Reducing the dimensionality of a system enhances quasiparticles interaction and leads to the formation of Coulomb bound complexes which govern most of the optical properties of semiconductors. Among these complexes, biexcitons are of special interest. Theoretically, first principle treatment of biexcitons, on the same theoretical footing as excitons and trions, is now possible thanks the the newly developed methodology of Ref. [1] which uses a hybrid approach combining configuration interaction and green function methods for the description of many-electrons many-holes excitations. This methodology is applied here to study the binding and fine structure of biexcitons in different transition metal dichalcogenides. The resulting binding energies agree better with experimental values a compared to previous effective mass treatment. The fine structure of biexcitons is shown to be highly dependent on temperature and become very dense (e.g. have many sub-peaks that are separated by hundreds of micro-eV to few meV) at room temperature.

[1] Torche, A., and Bester, G. (2019).PRB,100(20), 201403.