Can twinning stabilize B19′ structure in NiTi martensite?

► We study (100) compound twins in NiTi martensite from first principles. ► Optimization of several initial supercells led to identical resulting structures. ► Optimized lattice parameters are close to those of the experimental B19′ structure. ► Energy of (100) twinned cell is closer to that of B19′ cell than that of B33.