Localized surface electromagnetic waves in CrI${}_3$-based magnetophotonic structures

Abstract

Resulting from strong magnetic anisotropy two-dimensional ferromagnetism was recently shown to be stabilized in chromium triiodide, CrI${}_3$, in the monolayer limit. While its properties remain largely unexplored, it provides a unique material-specific platform to unveil its electromagnetic properties associated with coupling of modes. Indeed, trigonal symmetry in the presence of out-of-plane magnetization results in a non-trivial structure of the conductivity tensor, including the off-diagonal terms. In this paper, we study the surface electromagnetic waves localized in a CrI${}_3$-based structure using the results of {\it ab initio} calculations for the CrI${}_3$ conductivity tensor. In particular, we provide an estimate for the critical angle corresponding to the surface plasmon polariton generation in the Kretschmann-Raether configuration by a detailed investigation of reflectance spectrum as well as the magnetic field distribution for different CrI${}_3$ layer thicknesses. We also study the bilayer structure formed by two CrI${}_3$ layers separated by a SiO${}_2$ spacer and show that the surface plasmon resonance can be achieved at the interface between CrI${}_3$ and air depending on the spacer thickness.

11 pages, 6 figures