SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: Topological Semimetals

TT 6.7: Vortrag

Montag, 27. März 2023, 11:00–11:15, HSZ 304

Optically enhanced terahertz harmonic generation in the Dirac semimetal Cd₃As₂ — •Patrick Pilch¹, Changqing Zhu¹, Renato M. A. Dantas², Anneke Reinold¹, Yunkun Yang³, Faxian Xiu³, and Zhe Wang¹ — ¹TU Dortmund University, Germany — ²University of Basel, Switzerland — ³Fudan University, Shanghai, China

High harmonic generation provides an efficient tool to investigate nonequilibrium dynamics of a driven system, and is also very interesting for applications. Cd₃As₂ is a well-established three-dimensional Dirac semimetal with a topologically protected crossing of linear bands at the Fermi level. Terahertz harmonic generation is observed in Cd₃As₂ due to field-driven intraband kinetics [1]. By optically pumping the electron-doped Cd₃As₂, we observe a strong enhancement of the terahertz third harmonic generation. By investigating the dependence of the terahertz third harmonic generation on the pump fluence and time delay, we can ascribe this enhancement to the kinetics of a long-lived nonequilibrium state which corresponds to a population inversion of electrons and holes in the Dirac cone with a characteristic relaxation time τ≤ 10 ps.
[1] Kovalev, S. et al. Nature Commun. 11, 2451 (2020).