Fig. 1: Crystal structures and spectral characteristics of ReSe2 flakes.
From: Emergence of sliding ferroelectricity in naturally parallel-stacked multilayer ReSe2 semiconductor
a Top-view of the atomic arrangements in monolayer ReSe2. The four covalently bonded Re atoms in the unit cell arrange in a parallelogram and the adjacent parallelograms connect by covalent bonding along the b-axis forming a Re-chain. Purple and yellow spheres represent Re and Se atoms, respectively. b, c HAADF image of mechanically exfoliated ReSe2 flake along the [120] direction and the corresponding SAED pattern. UV-Vis-NIR absorption spectra (d), Raman spectra (e), and SHG signals (f) of ReSe2 with different thicknesses.
