Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 17: Two-dimensional Materials I (joint session HL/CPP)
HL 17.7: Vortrag
Dienstag, 2. April 2019, 11:15–11:30, H36
Zeeman splitting and inverted polarization of biexciton emission in monolayer WS2 — •Philipp Nagler1, Mariana V. Ballottin2, Anatolie A. Mitioglu2, Mikhail V. Durnev3, Takashi Taniguchi4, Kenji Watanabe4, Alexey Chernikov1, Christian Schüller1, Mikhail Glazov3, Peter C. M. Christianen2, and Tobias Korn1 — 1University of Regensburg — 2High Field Magnet Laboratory, Nijmegen — 3Ioffe Institute, St. Petersburg, Russia — 4NIMS, Tsukuba, Japan
Monolayer TMDCs are an ideal testbed to study the physics of quasiparticles in the two-dimensional limit. Besides excitons, more complex many-body states such as trions and biexcitons can emerge due to the strong Coulomb interaction in these materials. Here, we shed light on the intricate many-body physics of biexcitons in monolayer WS2 [1]. The encapsulation of the monolayer between two sheets of hBN significantly reduces the overall spectral broadening and allows us to observe biexciton emission with linewidths below 5 meV at 4 K. In magneto-PL experiments, we observe an inverted field-induced polarization, implying a preferential population of the high-energy peak in emission. We explain this unusual phenomenon by considering the evolution of the total energy of the biexciton complex in a magnetic field. Based on the experimental results and the developed model we are able to identify the momentum-space configuration of the optically dominant biexciton state of monolayer WS2.
P. Nagler et al., Phys. Rev. Lett. 121, 057402 (2018)