  The layered, air-stable van der Waals antiferromagnetic compound CrSBr
exhibits pronounced coupling between its optical, electronic, and magnetic
properties. As an example, exciton dynamics can be significantly influenced by
lattice vibrations through exciton-phonon coupling. Using low-temperature
photoluminescence spectroscopy, we demonstrate the effective coupling between
excitons and phonons in nanometer-thick CrSBr. By careful analysis, we identify
that the satellite peaks predominantly arise from the interaction between the
exciton and an optical phonon with a frequency of 118 cm-1 (~14.6 meV) due to
the out-of-plane vibration of Br atoms. Power-dependent and
temperature-dependent photoluminescence measurements support exciton-phonon
coupling and indicate a coupling between magnetic and optical properties,
suggesting the possibility of carrier localization in the material. The
presence of strong coupling between the exciton and the lattice may have
important implications for the design of light-matter interactions in magnetic
semiconductors and provides new insights into the exciton dynamics in CrSBr.
This highlights the potential for exploiting exciton-phonon coupling to control
the optical properties of layered antiferromagnetic materials.
