Study and control of electronic many-body states in two-dimensional materials

• Applicant: Professor Dr. Alexey Chernikov
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 287022282

Final Report Abstract

In summary, the project resulted in a number of advances in understanding the physics of Coulomb-correlated excitonic many-particle states in two-dimensional materials and exploring avenues for their external control. It ranged from studies of fundamental properties, such as the impact of external dielectric environment and dielectric disorder, to applications of external fields to change the composition of the optical excitation and manipulate their behavior. In terms of the experimental techniques, the project led to establishment of time- and spatially-resolved microscopy in the group as a useful and versatile tool to optically monitor propagation of light-emitting quasiparticles. It resulted not only in a number of studies within the framework of the Emmy Noether project but also triggered future developments towards studying mobile excitons in magnetic semiconductors, heterostructures and hybrid materials, or potentially exploring the impact of Wigner crystals on the exciton transport. Additional projects involve external dielectric control using excitons as sensors with high time resolution and creating dielectric confinement on the nanoscale. There are further opportunities towards more complex heterostructures and combinations of two-dimensional semiconductors with one- and zero-dimensional objects. In addition, the experimental work performed during the project also contributed to triggering theoretical developments on the subject of non-linear exciton diffusion and quantum transport phenomena, exciton-electron interactions, and THz-induced intra-excitonic processes. Altogether, the projects’ advances were reflected in both scientific output and the obtained qualifications of all project participants.

Publications

• Exciton Diffusion and Halo Effects in Monolayer Semiconductors. Physical Review Letters, 120(20).
  Kulig, Marvin; Zipfel, Jonas; Nagler, Philipp; Blanter, Sofia; Schüller, Christian; Korn, Tobias; Paradiso, Nicola; Glazov, Mikhail M. & Chernikov, Alexey
  
• Dielectric disorder in two-dimensional materials. Nature Nanotechnology, 14(9), 832-837.
  Raja, Archana; Waldecker, Lutz; Zipfel, Jonas; Cho, Yeongsu; Brem, Samuel; Ziegler, Jonas D.; Kulig, Marvin; Taniguchi, Takashi; Watanabe, Kenji; Malic, Ermin; Heinz, Tony F.; Berkelbach, Timothy C. & Chernikov, Alexey
  
• Autoionization and Dressing of Excited Excitons by Free Carriers in Monolayer WSe2. Physical Review Letters, 125(26).
  Wagner, Koloman; Wietek, Edith; Ziegler, Jonas D.; Semina, Marina A.; Taniguchi, Takashi; Watanabe, Kenji; Zipfel, Jonas; Glazov, Mikhail M. & Chernikov, Alexey
  
• Exciton diffusion in monolayer semiconductors with suppressed disorder. Physical Review B, 101(11).
  Zipfel, Jonas; Kulig, Marvin; Perea-Causín, Raül; Brem, Samuel; Ziegler, Jonas D.; Rosati, Roberto; Taniguchi, Takashi; Watanabe, Kenji; Glazov, Mikhail M.; Malic, Ermin & Chernikov, Alexey
  
• Nonclassical Exciton Diffusion in Monolayer WSe2. Physical Review Letters, 127(7).
  Wagner, Koloman; Zipfel, Jonas; Rosati, Roberto; Wietek, Edith; Ziegler, Jonas D.; Brem, Samuel; Perea-Causín, Raül; Taniguchi, Takashi; Watanabe, Kenji; Glazov, Mikhail M.; Malic, Ermin & Chernikov, Alexey
  
• Quasi-1D exciton channels in strain-engineered 2D materials. Science Advances, 7(44).
  Dirnberger, Florian; Ziegler, Jonas D.; Faria, Junior Paulo E.; Bushati, Rezlind; Taniguchi, Takashi; Watanabe, Kenji; Fabian, Jaroslav; Bougeard, Dominique; Chernikov, Alexey & Menon, Vinod M.
  
• Electron recoil effect in electrically tunable MoSe monolayers. Physical Review B, 105(7).
  Zipfel, Jonas; Wagner, Koloman; Semina, Marina A.; Ziegler, Jonas D.; Taniguchi, Takashi; Watanabe, Kenji; Glazov, Mikhail M. & Chernikov, Alexey
  
• Diffusion of Excitons in a Two-Dimensional Fermi Sea of Free Charges. Nano Letters, 23(11), 4708-4715.
  Wagner, Koloman; Iakovlev, Zakhar A.; Ziegler, Jonas D.; Cuccu, Marzia; Taniguchi, Takashi; Watanabe, Kenji; Glazov, Mikhail M. & Chernikov, Alexey
  
• Nonlinear and Negative Effective Diffusivity of Interlayer Excitons in Moiré-Free Heterobilayers. Physical Review Letters, 132(1).
  Wietek, Edith; Florian, Matthias; Göser, Jonas; Taniguchi, Takashi; Watanabe, Kenji; Högele, Alexander; Glazov, Mikhail M.; Steinhoff, Alexander & Chernikov, Alexey
  
• Ultrafast switching of trions in 2D materials by terahertz photons. Nature Photonics, 18(12), 1344-1349.
  Venanzi, Tommaso; Cuccu, Marzia; Perea-Causin, Raul; Sun, Xiaoxiao; Brem, Samuel; Erkensten, Daniel; Taniguchi, Takashi; Watanabe, Kenji; Malic, Ermin; Helm, Manfred; Winnerl, Stephan & Chernikov, Alexey