Extended Data Fig. 1: Crystal structure and basic optical properties of the GeSe crystal.
From: Reversible shuffle twinning yields anisotropic tensile superelasticity in ceramic GeSe
a, XRD pattern of the GeSe single crystal. The XRD pattern was obtained from the ground powder. The out-of-plane lattice constant c of 10.84 Å was obtained by using Bragg’s law. b, Raman spectrum of the GeSe single crystal. The four observed peaks at 81, 147, 172 and 185 cm−1, correspond to the Ag1, B3g, Ag2 and Ag3 modes, which is consistent with the reported results for GeSe with space group \({Pnma}\). c, Absorption spectrum of the GeSe single crystal. The inset in (c) shows an optical image of the as-grown GeSe single crystal. The optical bandgap of GeSe was determined to be around 1.2 eV, confirming the semiconducting nature of layered GeSe. d-f, Atomic crystal models (top panel) and HAADF-STEM images (bottom panel) of GeSe crystal along the [010], [100], and [001] orientations, respectively. In the model, Ge and Se atoms are colored in purple and green, respectively. From the STEM results, lattice constants can be determined as follows: a = 3.81 Å, b = 4.38 Å, and c = 10.80 Å.
