Extreme undercooling (down to 90K) of liquid metal nanoparticles

Abstract

Low-melting-point metal nanoparticles show remarkable undercoolings: exceptional values ΔT∕Tm≅0.5 were previously reported for confined Ga droplets in the 100–1000nm range. This was considered a characteristic limiting temperature for Ga. We here give evidence that Ga nanoparticles in the 3–15nm range can be undercooled at least down to 90K (ΔT∕Tm⩾0.7) without crystallization. Since computations and experiments on clusters with <50 atoms show on the contrary the signatures of melting at temperatures well above the bulk value, the result is particularly relevant in stressing the importance of interfacial and finite-size effects on the thermodynamics of the nanoscale.