What is Half-Solidity?
2014.03.20 20:56
A new dynamic melting state, which has both solid and liquid characteristics, is revealed from first-principles molecular dynamics simulations of Al55 clusters. In thermal fluctuations near the melting point, the low-energy tetrahedral-like Al55 survives through rapid, collective surface transformations—such as parity conversions and correlated diffusion of two distant vacancies—without losing its structural orders. The emergence of the collective motions is solely due to efficient thermal excitation of soft phonon modes at nanoscale. A series of spontaneous surface reconfigurations result in a mixture or effective flow of surface atoms as is random color shuffling of a Rubik’s cube. This novel flexible solid state (termed as half-solidity) provides useful insights into understanding stability, flexibility, and functionality of nanosystems near or below melting temperatures.
http://pubs.acs.org/doi/abs/10.1021/nn901536a
Movie: http://pubs.acs.org/doi/suppl/10.1021/nn901536a/suppl_file/nn901536a_si_002.mpg
J. Kang et al., ACS Nano - Jan. 8, 2010
