High-refractive index and mechanically cleavable non-van der Waals InGaS3

Abstract The growing family of two-dimensional crystals has been recognized as a promising platform for investigation rich low-dimension physics and production variety devices. Of particular interest are recently reported atomic sheets non-van der Waals materials, which reshape our understanding chemical bonds enable heterostructures with novel functionality. Here, we study the structural optical properties ultrathin InGaS 3 produced by standard mechanical cleavage. Our ab initio calculations reveal weak out-of-plane covalent bonds, responsible layered structure material. energy required isolation single layer is low ~50 meVÅ –2 , comparable conventional van material’s monolayer energies 20–60 . A comprehensive structural, vibrational, material reveals its wide bandgap (2.73 eV), high refractive index (>2.5) negligible losses in visible infrared spectral ranges. These make it perfect candidate visible-range all-dielectric nanophotonics.