Extended Data Fig. 10: Loading direction dependence of superelasticity in GeSe.
From: Reversible shuffle twinning yields anisotropic tensile superelasticity in ceramic GeSe
The TEM images show typical fabricated GeSe samples for both the DT and PTP testing under a large strain with \(\theta\) (\(\theta\) is denoted as the angle between the zigzag direction and loading direction) ranging from 0 to 360° in steps of ~15°. Insets are SAED patterns of the tested samples; the scale bar is 5 nm−1. The zigzag direction of each sample is indexed by a red arrow, and the stripy domains generated due to tensile strain are highlighted by blue dashed lines. The orange arrows indicate fracture of the tested samples under a large strain. The schematic diagram in the center illustrates the range of tensile directions for the appearance of superelasticity in GeSe. The balls represent the experimentally measured values of \(\theta\), among which the orange balls highlight the superelastic case and the blue balls highlight the elastic case. One can see that the fabricated PTP samples are able to exhibit observable stripy domains (indicative of superelasticity) only when \(\theta\) lies in the range from 325° to 30° (or 145° to 210°). Otherwise, the GeSe samples show no sign of stripy domains until they are stretched to fracture during loading. This finding indicates that superelasticity is highly anisotropic in GeSe.
