Speaker
Description
The recently discovered group of intercalated monolayers with structural formula MA$_2$Z$_4$ attracted significant interest due to the wide range of physical properties [1]. In the talk we discuss the $\alpha$-NbSi$_2$N$_4$ monolayer as a two-dimensional ferromagnet with promising magnetic, thermal and optical properties for future spintronics applications. Specifically, using density functional theory (DFT) we study mechanical stability and possibility of charge density waves formation. We examine the dielectric properties within the Random Phase Approximation [2] and discuss the effect of the overlap matrix elements and constant matrix element approximation on electronic susceptibility. Optical conductivity based on the Berry curvature calculations, and orbital magnetization were analyzed using an effective model with a localized Wannier basis. The magnetic properties were studied within the classical Heisenberg model with a uniaxial anisotropy term. The model parameters were determined by mapping the total electronic energy for different magnetic configurations to the model. Magnon dispersions and Curie temperature using Monte Carlo simulations are discussed.
Acknowledgements
This work was supported by the Slovak Research and Development Agency under the Contract no. SK-SRB-23-0033, VEGA Grant No. 1/0104/25, Slovak Academy of Sciences project IMPULZ IM-2021-42.
References
[1] L. Wang et al., Intercalated architecture of MA$_2$Z$_4$ family layered van der Waals materials with emerging topological, magnetic and superconducting properties, Nature Comm. 12, (2021).
[2] J. Sólyom, Fundamentals of the Physics of Solids (Springer Berlin Heidelberg, 2010).
