Computational discovery of high-refractive-index van der Waals materials: The case of HfS${}_2$

Abstract

New high-refractive-index dielectric materials may enhance many optical technologies by enabling efficient manipulation of light in waveguides, metasurfaces, and nanoscale resonators. Van der Waals materials are particularly promising due to their excitonic response and strong in-plane polarizability. Here we combine ab initio calculations and experiments to discover new high-refractive-index materials. Our screening highlights both known and new promising optical materials, including hafnium disulfide (HfS${}_2$), which shows an in-plane refractive index above 3 and large anisotropy in the visible range. We confirm these theoretical predictions through ellipsometry measurements and investigate the photonic potential of HfS${}_2$ by fabricating nanodisk resonators, observing optical Mie resonances in the visible spectrum. Over the course of seven days, we observe a structural change in HfS${}_2$, which we show can be mitigated by storage in either argon-rich or humidity-reduced environments. This work provides a comparative overview of high-index van der Waals materials and showcases the potential of HfS${}_2$ for photonic applications in the visible spectrum.

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References in corpus (6)

• High-Q supercavity modes in subwavelength dielectric resonators
• GPAW: An open Python package for electronic-structure calculations
• Van der Waals Materials for Applications in Nanophotonics
• Super-Resolution Nanolithography of Two-Dimensional Materials by Anisotropic Etching
• Ultraviolet Mie resonances in computationally discovered boron phosphide nanoparticles
• Quality factor of dielectric optical resonators