Transient reflectance of photoexcited Cd₃As₂

Authors

Christopher P. Weber, Santa Clara UniversityFollow
Ernest Arushanov
Bryan S. Berggren
Tahereh Hosseini
Nikolai Kouklin
Alex Nateprov

Document Type

Article

Publication Date

6-8-2015

Publisher

American Institute of Physics Publishing

Abstract

We report ultrafast transient-grating measurements of crystals of the three-dimensional Dirac semimetal cadmium arsenide, Cd₃As₂, at both room temperature and 80 K. After photoexcitation with 1.5-eV photons, charge-carriers relax by two processes, one of duration 500 fs and the other of duration 3.1 ps. By measuring the complex phase of the change in reflectance, we determine that the faster signal corresponds to a decrease in absorption, and the slower signal to a decrease in the light's phase velocity, at the probe energy. We attribute these signals to electrons' filling of phase space, first near the photon energy and later at lower energy. We attribute their decay to cooling by rapid emission of optical phonons, then slower emission of acoustic phonons. We also present evidence that both the electrons and the lattice are strongly heated.

Comments

Copyright © 2015 American Institute of Physics Publishing. Reprinted with permission.

Recommended Citation

Weber, C. P., Arushanov, E., Berggren, B. S., Hosseini, T., Kouklin, N., & Nateprov, A. (2015). Transient reflectance of photoexcited Cd₃As₂. Applied Physics Letters, 106(23), 231904. https://doi.org/10.1063/1.4922528