In‐Plane Twinning Defects in Hexagonal GeSb ₂ Te ₄

Ge–Sb–Te (GST) alloys are an important family of phase-change materials employed in non-volatile memories and neuromorphic devices. Conventional memory cells based on GST rely the switching between amorphous state a metastable, disordered rocksalt-like phase. Recently, however, it has been proposed that special type defect layer-structured GST—the so called “swapped bilayer” defect—is responsible for novel mechanism observed GST-based superlattices. Thus, disorder appears to play role both types mechanisms. Here, observation new in-plane twinning hexagonal GeSb2Te4 by direct atomic-scale imaging experiments is reported, which serves as key ingredient account abundance inverted stacking faults Ab initio simulations reveal low energy cost these extended defects, indicate such defects can affect electrical properties inducing electron localization. This work provides additional insight into nature effects structural materials.