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  • Letter
  • Open Access

Light wave induced nanosecond-long persistent state in the Dirac semimetal Cd3As2

Ahmed Ghalgaoui1,2,*, Patrick Pilch1, Taehee Kang2,3, Matthias Runge2, Sergey Kovalev1, Yunkun Yang4, Faxian Xiu4, and Zhe Wang1

  • *Contact author: ahmed.ghalgaoui@tu-dortmund.de
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Phys. Rev. B 113, L041106 – Published 6 January, 2026

DOI: https://doi.org/10.1103/yj4s-7ks7

Abstract

Unraveling light induced ultrafast dynamics in three-dimensional Dirac materials is crucial for deepening our fundamental understanding and for advancing potential optoelectronic applications. While time-resolved pump-probe spectroscopy has predominantly revealed carrier dynamics governed by Dirac fermion cooling and population inversion, the full picture of relaxation pathways remains incomplete. In this Letter, we identify a relaxation channel in these materials. Using strong terahertz (THz) field excitation combined with a near-infrared (NIR) probe, we detect a long-lived carrier population persisting on the nanosecond timescale. This extended lifetime suggests that carriers become trapped in defect states, leading to sub-band-gap absorption in the NIR and pointing to the significant role of defect-assisted relaxation in the carrier dynamics of Dirac semimetals.

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Outline

Information

Phys. Rev. B 113, L041106– Published 6 January, 2026
  • Received 21 August 2025
  • Revised 9 December 2025
  • Accepted 22 December 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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