Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Poster 1

HL 25.41: Poster

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

Nonlinear dynamics of Dirac fermions in topological HgTe structures — •Tatiana Aureliia Uaman Svetikova1, Alexej Pashkin1, Thales Oliveira1, Florian Bayer2, Christian Berger2, Lena Fürst2, Hartmut Buhmann2, Laurens W. Molenkamp2,3, Manfred Helm1, Tobias Kiessling2, Stephan Winnerl1, Sergey Kovalev1, and Georgy V. Astakhov11HZDR, Dresden, Germany — 2Physikalisches Institut (EP3), Universität Würzburg, Würzburg, Germany — 3Institute for Topological Insulators, Würzburg, Germany

High harmonic generation has applications in various fields, including ultrashort pulse measurements, material characterization and imaging microscopy. Strong THz nonlinearity and efficient third harmonic generation (THG) were demonstrated in graphene [1], therefore it is natural to assume the presence of the same effect in other Dirac materials, such as topological insulators (TI)[2].

We used a series of HgTe samples corresponding to three qualitatively different cases: 2D trivial and topological structures and 3D TIs. By using moderate THz fields, the presence of highly efficient THG was measured at different temperatures and THz powers. This provides insight into physical mechanisms leading to THG in TIs. For in-depth understanding of Dirac fermions dynamics and dominating scattering mechanisms in HgTe TI, we conducted THz pump-probe experiments that reveal several relaxation time scales.

[1] Hafez, H. A. et al., Nature 561, 507 (2018).

[2] Kovalev, S. et al., Quantum Mater. 6, 84 (2021

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