Fig. 1: Crystal structure and interlayer binding energies of non-van der Waals InGaS3.
From: High-refractive index and mechanically cleavable non-van der Waals InGaS3
a 5X optical micrograph of bulk crystal on a glass slide. Inset: Top and side views of P65 space group hexagonal crystal structure with lattice constants of a = b = 6.6 Å, c = 17.9 Å. a, b, c and a*, b*, c* label real and reciprocal space crystallographic axes, correspondingly. b X-ray diffraction micrograph of the crystal presented in panel (a) across a*b*-plane. c Same as (b), but across c*b*-plane. d Schematic illustration of layer separation achieved by cutting off the weak non-van der Waals bonds. UC, 1 L stand for unit cell and cleaved monolayer, respectively. e Typical exfoliation energies of conventional van der Waals (black pentagons) and non-van der Waals (red pentagons) materials evaluated via first principles calculations. Green hexagon presents our estimation of the exfoliation energy along the proposed minimal energy atomic plane.
