Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 41: Topological Semimetals

TT 41.2: Vortrag

Mittwoch, 11. März 2026, 09:45–10:00, HSZ/0103

Terahertz third-harmonic generation of lightwave-driven Weyl fermions far from equilibrium — •Patrick Pilch¹, Changqing Zhu¹, Sergey Kovalev^1,2, Renato M. A. Dantas^3,4, Amilcar Bedoya-Pinto^5,6, Stuart S. P. Parkin⁵, and Zhe Wang¹ — ¹TU Dortmund University, Germany — ²Helmholtz-Zentrum Dresden-Rossendorf, Germany — ³University of Basel, Switzerland — ⁴University of Minho, Portugal — ⁵Max Planck Institute for Microstructure Physics, Halle, Germany — ⁶University of Valencia, Spain

We report on time-resolved ultrafast terahertz third- harmonic generation spectroscopy of nonequilibrium dynamics of Weyl fermions in a nanometer thin film of the Weyl semimetal TaP [1]. Terahertz third-harmonic generation is observed at room temperature under the drive of a multicycle narrowband terahertz pulse with a peak field strength of down to tens of kV/cm. The observed terahertz third-harmonic generation exhibits a perturbative cubic power-law dependence on the terahertz drive. By varying the polarization of the drive pulse from linear to elliptical, we realize a sensitive tuning of the third harmonic yield. By carrying out theoretical analysis based on the Boltzmann transport theory, we can properly describe the experimental results and ascribe the observed THz nonlinearity to field-driven kinetics of the Weyl fermions.
[1] P. Pilch et al., Nano Lett. (2025), DOI: 10.1021/acs.nanolett.5c04143

Keywords: Weyl semimetal; terahertz third-harmonic generation; perturbative nonlinear responses; nonperturbative nonlinear responses; Boltzmann transport theory