Characterization of non-affine displacement fields of amorphous solids in three dimensions*

Amorphous solids exhibit large non-affine displacement fields in response to applied stress. In crystalline solids, topological defects cause non-affine displacements. However, the structural origins of the non-affine displacements in amorphous solids are difficult to identify due to the lack of long-range structural order. In previous studies, we employed Delaunay triangularization to characterize the non-affine displacement fields in two-dimensional binary Lennard-Jones solids undergoing athermal, quasistatic simple shear (AQS). We showed that quadrupolar displacement fields are most frequently observed and these are generated by pure shear defects of single Delaunay triangles. Here, we explore the structure and evolution of the displacement fields in binary Lennard-Jones solids undergoing AQS in three dimensions (3D) using Delaunay tetrahedralization. We find that quadrupolar and octopolar non-affine displacement fields occur in 3D. In addition, we identify the local strains of the single tetrahedra that give rise to these displacement fields.