MultiShifter: Software to generate structural models of extended two-dimensional defects in 3D and 2D crystals

Abstract Extended defects in crystals, such as dislocations, stacking faults and grain boundaries, play a crucial role in determining a wide variety of materials properties. Extended defects can also lead to novel electronic properties in two-dimensional materials, as demonstrated by recent discoveries of emergent electronic phenomena in twisted graphene bilayers. This paper describes several approaches to construct crystallographic models of two-dimensional extended defects in crystals for first-principles electronic structure calculations, including (i) crystallographic models to parameterize generalized cohesive zone models for fracture studies and meso-scale models of dislocations and (ii) crystallographic models of twisted bilayers. The approaches are implemented in an open source software package called M ulti S hifter .