Hochaufgelöste Spektroskopie an Rydbergexzitonen in äußeren Feldern
Zusammenfassung der Projektergebnisse
Based on the substantial prior work on Rydberg excitons performed in the Dortmund group, the present project mainly focused on studies of Rydberg excitons in external magnetic or/and electric fields with high spectral resolution, which was limited only by the spectral resolution of the cw dye lasers used in the transmission studies, which amounts to few neV. The sensitivity of Rydberg exciton states to external fields shows a drastic scaling with the principal quantum number n of the Rydberg exciton state. Accordingly, Rydberg excitons proved to be an ideal model system to study similarities and differences between atomic and semiconductor systems with respect to their interaction with electric or magnetic fields. Within this project, we performed a detailed study of several central effects in the field of Rydberg excitons. Due to space limitations, here I will focus on two of them: Their dissociation in electric fields and the magneto-Stark effect. We performed a detailed investigation of the behavior of Rydberg excitons in electric fields. As expected, the Rydberg states belonging to a certain quantum number split into a Stark fan of states which will eventually dissociate in large enough fields. However, it turned out that the stability of these states differs strongly. Surprisingly, we could show that the lowest energy states are the first states to dissociate. We were able to explain this finding by taking not only the energy of the states, but also the spatial shape of the exciton wavefunction into account. Second, we demonstrated the so-called magneto-Stark effect, which is a genuine semiconductor effect and does not routinely occur in atomic systems. It arises due to the fact that an exciton created inside a crystal is usually not at rest. As a consequence, significant differences arise when it is subjected to an external magnetic field in the Faraday or Voigt configuration. In particular, additional absorption lines appear in Voigt geometry due to additional symmetry breaking. Dr. Julian Heckötter has been awarded the award for the best PhD thesis of the faculty of physics of TU Dortmund university for his thesis which includes results obtained within this project.
Projektbezogene Publikationen (Auswahl)
-
Dissociation of excitons in Cu2O by an external field, Phys. Rev. B 98, 102, 035150 (2018)
Julian Heckötter, Marcel Freitag, Dietmar Fröhlich, Marc Aßmann, Manfred Bayer, Marina. A. Semina, Misha M. Glazov
-
Influence of magnetic confinement on the yellow excitons in Cuprous Oxide subject to an electric field, Phys. Solid State 60, 1595 (2018)
Julian Heckötter, Dietmar Fröhlich, Marc Aßmann, Manfred Bayer
-
Landau-Level quantization of the yellow exciton series in Cuprous Oxide, Phys. Solid State 60, 1625 (2018)
Julian Heckötter, Johannes Thewes, Dietmar Fröhlich, Marc Aßmann, Manfred Bayer
-
Magneto-Stark effect of Rydberg excitons in Cuprous Oxide, Phys. Rev. B 98, 085206 (2018)
Patric Rommel, Frank Schweiner, Jörg Main, Julian Heckötter, Marcel Freitag, Dietmar Fröhlich, Kevin Lehninger, Marc Aßmann, Manfred Bayer
-
Semiconductor Rydberg Physics, Advanced Quantum Technologies 3, 1900134 (2020)
Marc Aßmann, Manfred Bayer
-
Coherent transfer matrix analysis of the transmission spectra of Rydberg excitons in Cuprous Oxide, Phys. Rev. B 104, 035206 (2021)
Heinrich Stolz, Rico Schwartz, Julian Heckötter, Marc Aßmann, Dirk Semkat, Sjard O. Krüger, Manfred Bayer
