Seminar: Ultrafast magnetism in the 2D semiconductor ferromagnet CrI3

Abstract: Femtosecond laser induced spin dynamics in magnets exhibits a rich diversity of the underlying physical processes. Generally, it is explained by the mutual interaction among different degrees of freedom including electrons, spins and lattice [1]. With the advent of van der Waals bonded layered ferromagnetic materials possessing strong light matter interactions, it presents an interesting opportunity to control spin dynamics with ultrafast lasers [2] in 2D systems. Here, we investigate CrI3, a semiconducting 2D ferromagnet with optical and magneto-optical properties that are dominated by excitons and charge transfer processes [3]. We use time resolved magneto-optical technique with a cryostat in FREIA laser lab to observe the dynamics in CrI3 below its Tc~61 K. We will discuss the role of fs pulse excited excitons, coherent phonons and polaron hopping altering the exchange interactions in CrI3 after laser excitation.

References:

1. Tauchert et. al. Nature 602, 73 (2022)

2. Padmanabhan et. al., Nature Communications 13, 4473 (2022)

3. Xufeng Li et al., Nano Lett. 22, 8755 (2022)