Contact
Dr. Stephan Winnerl
Head Spectroscopy
s.winnerl
hzdr.de
Phone: +49 351 260 3522
Bachelor, Master, and Doctoral Theses
We are continuously looking for students to join our topics. If you are interested, please get in touch with the contact person listed or with Dr. Stephan Winnerl.
Carrier dynamics in graphene
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| Pump probe signals for different photon energies, corresponding microscopic calculations and energy diagram. As the photon energy is reduced to values below the optical phonon energy of about 200 meV, the relaxation is significantly slowed down. |
Graphene, i.e. a single layer of hexagonally arranged carbon atoms, features a gapless band structure with linear dispersion. We study the carrier dynamics of Dirac electrons in graphene, also Landau quantized graphene and graphene-based plasmonic samples and develope graphene-based divices such as ultrafast broadband detectors.
Related publications
J.W. Han, P. Sai, D.B. But, E. Uykur, S. Winnerl, G. Kumar, M.L. Chin, R.L. Myers-Ward, M.T. Dejarld, K.M. Daniels, T.E. Murphy, W. Knap, and M. Mittendorff
Strong transient magnetic fields induced by THz-driven plasmons in graphene disks
Nature Comm. 14, 7493 (2023).
J. W. Han, M. L. Chin, S. Matschy, J. Poojali, A. Seidl, S. Winnerl, H. A. Hafez, D. Turchinovich, G. Kumar, R. L. Myers-Ward, M. T. Dejarld, K. M. Daniels, H. D. Drew, T. E. Murphy, M. Mittendorff
Plasmonic terahertz nonlinearity in graphene disks
Adv. Photonics Res. 3, 210021 (2022).
D. B. But, M. Mittendorff, C. Consejo, F. Teppe, N. N. Mikhailov, S. A. Dvoretskii, C. Faugeras, S. Winnerl, M. Helm, W. Knap, M. Potemski, and M. Orlita, Suppressed Auger scattering and tunable light emission of Landau-quantized massless Kane electrons, Nature Photonics 13, (2019)
M. M. Jadidi, K. M. Daniels, R. L. Myers-Ward, D. K. Gaskill, J. C. König-Otto, S. Winnerl, A. B. Sushkov, H. D. Drew, T. E. Murphy, and M. Mittendorff, Optical Control of Plasmonic Hot Carriers in Graphene, ACS Photonics 6, 302 (2019)
S. Brem, F. Wendler, S. Winnerl, and E. Malic, Electrically pumped graphene-based Landau-level laser, Phys. Rev. Mat. 2, 034002 (2018)
S. Winnerl, M. Mittendorff, J. C. König-Otto, H. Schneider, M. Helm, T. Winzer, A. Knorr, and E. Malic, Ultrafast processes in graphene: from fundamental manybody interactions to device applications, Annalen der Physik (Berlin) 529, 1700022 (2017)
E. Malic, T. Winzer, F. Wendler, S. Brem, R. Jago, A. Knorr, M. Mittendorff, J. C. König-Otto, T. Plötzing, D. Neumaier, H. Schneider, M. Helm, and S. Winnerl, Carrier dynamics in graphene: ultrafast many-particle phenomena, Annalen der Physik (Berlin) 529, 1700038 (2017)
J. C. König-Otto, Y. Wang, A. Belyanin, C. Berger, W. A. de Heer, M. Orlita, A. Pashkin, H. Schneider, M. Helm, and S. Winnerl, Four-Wave Mixing in Landau-Quantized Graphene, Nano Lett. 17, 2184 (2017)
F. Wendler, M. Mittendorff, J. C. König-Otto, S. Brem, C. Berger, W. A. de Heer, R. Böttger, H. Schneider, M. Helm, S. Winnerl, and E. Malic, Symmetry-Breaking Supercollisions in Landau-Quantized Graphene, Phys. Rev. Lett. 119, 067405 (2017)
J. C. König-Otto, M. Mittendorff, T. Winzer, F. Kadi, E. Malic, A. Knorr, C. Berger, W. A. de Heer, A. Pashkin, H. Schneider, M. Helm, and S. Winnerl, Slow noncollinear Coulomb scattering in the vicinity of the Dirac point in graphene, Phys. Rev. Lett. 117, 087401 (2016)
M. Mittendorff, F. Wendler, E. Malic, A. Knorr, M. Orlita, M. Potemski, C. Berger, W. A. de Heer, H. Schneider, M. Helm, and S. Winnerl, Carrier dynamics in Landau-quantized graphene featuring strong Auger scattering, Nature Physics 11, 75 (2015)
M. Mittendorff, M. Orlita, M. Potemski, C. Berger, W. A. de Heer, H. Schneider, M. Helm, and S. Winnerl, Intraband carrier dynamics in Landau-quantized multilayer epitaxial graphene, New J. Phys. 16, 123021 (2014)
M. Mittendorff, T. Winzer, E. Malic, A. Knorr, C. Berger, W.A. de Heer, H. Schneider, M. Helm, and S. Winnerl, Anisotropy of excitation and relaxation of photogenerated Dirac electrons in graphene, Nano Lett. 8, 1504 (2014)
M. Mittendorff, S. Winnerl, J. Kamann, J. Eroms, D. Weiss, H. Schneider, and M. Helm, Ultrafast graphene-based broadband THz detector, Appl. Phys. Lett. 103, 021113 (2013)
S. Winnerl, F. Göttfert, M. Mittendorff, H. Schneider, M. Helm, T. Winzer, E. Malic, A. Knorr, M. Orlita, M. Potemski, M. Sprinkle, C. Berger, and W.A. de Heer, Time-resolved spectroscopy on epitaxial graphene in the infrared spectral range: relaxation dynamics and saturation behavior, J. Phys.: Condens. Matter 25, 054202 (2013)
S. Winnerl, M. Orlita, P. Plochocka, P. Kossacki, M. Potemski, T. Winzer, E. Malic, A. Knorr, M. Sprinkle, C. Berger, W.A. de Heer, H. Schneider, and M. Helm, Carrier relaxation in epitaxial graphene photoexcited near the Dirac point, Phys. Rev. Lett. 107, 237401 (2011)
