PNNL

Abstract

Understanding the atomically precise arrangement of atoms at epitaxial interfaces is important for emerging technologies such as quantum materials that have function and performance dictated by bonds and defects that are energetically active on the eV scale. A combination of atomistic modeling and dislocation theory analysis describes both primary and secondary dislocation networks at the metamorphic Al/Si (111) interface, which is experimentally validated by atomic resolution scanning transmission electron microscopy. The electron microscopy images show primary misfit dislocations for the majority of the strain relief, and evidence of a secondary structure allowing for complete relaxation of the Al-Si misfit strain. This study implicates a path for growth of special highly-mismatched single-crystal interfaces with complete strain relief in an atomically abrupt structure, which may open a new chapter in studying new materials pairs and enable a new generation of metamorphic materials and devices.