Abstract
At the triple point of a repulsive screened Coulomb system, a fcc crystal, a bcc crystal, and a fluid phase coexist. At their intersection, these three phases form a liquid groove, the triple junction. Using confocal microscopy, we resolve the triple junction on a single-particle level in a model system of charged PMMA colloids in a nonpolar solvent. The groove is found to be extremely deep and the incommensurate solid-solid interface to be very broad. Thermal fluctuations hence appear to dominate the solid-solid interface. This indicates a very low interfacial energy. The fcc-bcc interfacial energy is quantitatively determined based on Young’s equation and, indeed, it is only about 1.3 times higher than the fcc-fluid interfacial energy close to the triple point.
- Received 11 May 2017
DOI:https://doi.org/10.1103/PhysRevLett.119.128001
© 2017 American Physical Society