In the huge family of metal, copper (Cu) is one of the earliest documented used materials and is also widely applied in modern society.Due to the superior electrical, thermal, and mechanical properties, Cu has been extensively used as electrical conductors,thermal dissipaters and structure components.Currently, most of these applications are based on the polycrystalline Cu that can be produced at large scale through mature manufacturing techniques.With the rapid development of science and technology, singlecrystal Cu that contains no grain boundaries and very few defects,is urgently demanded, especially in the top-end applications like high-speed communications, low-power electronics and selective catalysis.Unfortunately, the production of large single-crystal Cu remains challenging and prohibitively expensive for most applications.