Ultrafast, Free Growth of Low-Dislocation-Density Large-Sized Bulk Copper Single Crystals under High Magnetic Field

Synthesis of bulk copper single-crystal (CSC) materials with low dislocation densities has garnered considerable interest because of their exceptional mechanical and electrical properties, particularly for applications in integrated circuits and graphene synthesis. However, realizing a cost-effective mass production of large CSCs remains challenging. Here, we report an ultrafast growth strategy (growth rate on the order of millimeters per second) for synthesizing bulk CSCs, with low dislocation densities, under a high magnetic field (HMF). During the directional growth of pure copper, the HMF increases the probability of single-crystal formation by lowering the nucleation undercooling temperature and increasing the thickness of the thermal boundary layer. It also smooths the solid–liquid interface, which is conducive to the stable growth of CSCs. The large-sized bulk CSCs, synthesized under an HMF and featuring low dislocation densities and high crystallinity, exhibit low microhardness and annealing-induced high electrical conductivity. This method is further extended to the fabrication of Cu/Fe alloys, pure germanium, and zinc single crystals. This paper offers technological and theoretical guidance for the ultrafast, low-cost, large-scale production of high-quality CSC wires for large-scale applications.