SKM 2023 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 17: THz and MIR physics in semiconductors
HL 17.10: Vortrag
Dienstag, 28. März 2023, 12:15–12:30, JAN 0027
Optically excited charge-carrier dynamics in the antiferromagnetic semiconductor MnTe — •Changqing Zhu1, Patrick Pilch1, Anneke Reinold1, Gunther Springholz2, Mirko Cinchetti1, and Zhe Wang1 — 1TU Dortmund University, Germany — 2Johannes Kepler University of Linz, Austria
Room-temperature antiferromagnetic semiconductors are very interesting for possible spintronic applications. With a long-range antiferromagnetic order (TN = 307 K) at room temperature, the hexagonal α-MnTe is a relevant candidate for those applications. Here we report on time-resolved measurements of ultrafast dynamics of optically excited charge carriers in α-MnTe thin film, by optical pump - optical probe and optical pump - THz probe spectroscopic techniques at room temperature. In contrast to a phononic oscillation mode at 5.3 THz as observed by 2.4 eV pump [1], our studies with an 1.5 eV pump pulse cannot reveal the optical phonon mode but rather low-energy acoustic phonon-like behavior at high pump fluence. Moreover, nonlinear dependence on pump fluence is observed both in our optical and terahertz probes, for a pump fluence above ∼ 2.0 mJ/cm 2 . This indicates a different physical mechanism than in the previous studies. The observed relaxation processes can be associated to electron-hole recombination and electron-phonon scattering.
[1] D. Bossini et al. Phys. Rev. B 104, 224424 (2021).