Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Poster 1

HL 25.18: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P2

Tunable THz-absorption and gain in transition metal dichalcogenides — •Josefine Neuhaus, Tineke Stroucken, and Stephan W. Koch — Philipps University, Marburg, Germany

Exhibiting linear optical spectra that are dominated by strongly bound excitonic features, transition metal dichalcogenides have attracted considerable interest in the past decade. In a properly pre-excited system, it is possible to study intra-excitonic transitions between optically bright s- and dark p-type excitons by their THz-absorption. In particular, as p-type states lie energetically below s-type states of equal main quantum number, not only absorptive but also gain features can be observed. Furthermore, the application of an external magnetic field perpendicular to the sample results in a shift of the various excitonic resonances. As the induced Zeeman shift depends on the angular momentum quantum number, the magnetic field induced shift differs for s- and p-type excitonic states, enabeling a tunability of the intra-excitonic transitions. Here, we study the tunability of the intra-excitonic absorption and gain spectra upon the interplay of an applied magnetic field, the dielectric environment and the material parameters by means of a combined approach based on DFT and a Semiconductor-Bloch equation approach.