Ultrahigh hardness and improved ductility for nanotwinned mercury cadmium telluride

Unidirectionally coherent and boundary-free nanotwinned (nt) mercury cadmium telluride (HgCdTe or MCT) was achieved under plastic deformation of nanoindentation. The hardness of nt-MCT is up to 47.2 GPa, which is two orders magnitude higher than that of monocrystalline MCT. This increased hardness originates from the unique composite nt structure, which exhibits a repeated pattern comprising a lamellar twin >11.5 nm thick, followed by one or several lamellar twins with thicknesses <11.5 nm.