Structures of Sn nanoparticles and nanowires are studied using density
functional theory in conjunction with thermodynamic considerations. Besides
the low-temperature α and room-temperature β phases, the high-temperature γ
phase is considered. Results show that at ambient temperatures for sizes
smaller than 50 nm, metallic β- and γ-Sn nanoparticles are more stable than
semimetallic α-Sn ones because of their lower surface energies. Moreover, very
small Sn nanostructures, exemplified by nanowires, are expected to exhibit the
γ phase even at 0 K
