Dimensionality dependent electronic structure in exfoliated van-der-Waals antiferromagnet NiPS3

Exfoliable magnetic van-der-Waals (vdW) materials present a remarkable opportunity to explore fundamental theorems of magnetism in 2D [1]. Of particular interest is NiPS3, an exfoliable material exhibiting both magnetic order and strong correlations [2], ordering antiferromagnetically at TN=155 K. Interestingly, recent Raman measurements find evidence that vanishing long-range magnetic order in monolayer NiPS3 [3] is characteristic of a 2D XY model. In this talk, I will present the results of our Resonant Inelastic X-ray Scattering (RIXS) experiment on exfoliated NiPS3, which revealed a thickness reliant electronic structure, systematic dependence of charge transfer (CT) energy scales, and increasing CT gaps and hybridization for exfoliated flakes approaching the 2D limit. Given the continued interest in exfoliable vdW materials, it is crucial to understand how local electronic structures change with decreased dimensionality, as can only be done using RIXS. These results will provide a detailed picture of how thickness influences the electronic structure in vdW materials and lay the groundwork to expand resonant x-ray techniques to the 2D limit. 

[1] Kenneth S. Burch et al. Nature 563, 47–52 (2018)

[2] Chen-Tai Kuo et al. Scientific Reports 6, 20904 (2016)

[3] K. Kim et al. Nature Communications 10, 1038 (2019)