Title: Atomic scale study of grain boundaries in low-symmetry two dimensional ReS2

Abstract

Grain boundaries (GBs) are significant microstructures that dominate properties of polycrystalline two-dimensional (2D) materials. Low-symmetry monolayer rhenium disulfide (ReS2), which belongs to the triclinic crystal system and displays abundant anisotropic properties, provides an ideal platform to investigate diverse configurations of GBs and their orientation-dependent characteristics. Here, we combine aberration-corrected scanning transmission electron microscopy and density functional theory (DFT) calculations to investigate the atomic configurations, electronic band structure and facture mechanics of both atomically stitched and overlapping GBs in chemical vapor deposition-grown polycrystalline ReS2 monolayers. Our results provide fundamental insights into the impact of GBs on material’s electronic and mechanical properties, thus helping establish a more comprehensive understanding between the macroscopic performance and the microscopic structure of 2D materials.