Two features at the two-dimensional freezing transitions.
We studied the two-dimensional freezing transitions in monolayers of microgel colloidal spheres with short-ranged repulsions in video-microscopy experiments, and monolayers of hard disks, and Yukawa particles in simulations. These systems share two common features at the freezing points: (1) the bimodal distribution profile of the local orientational order parameter; (2) the two-body excess entropy, s(2), reaches -4.5±0.5 k(B). Both features are robust and sensitive to the freezing points, so that they can potentially serve as empirical freezing criteria in two dimensions. Compared with the conventional freezing criteria, the first feature has no finite-size ambiguities and can be resolved adequately with much less statistics; and the second feature can be directly measured in macroscopic experiments without the need for microscopic information.
Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Ziren
Z
Wang
Weikai
W
Qi
Yi
Y
Peng
Ahmed M
AM
Alsayed
Yong
Y
Chen
Penger
P
Tong
Yilong
Y
Han
D000178:Acrylamides / Q000737:chemistry; D003102:Colloids / Q000737:chemistry; D005615:Freezing; D005782:Gels / Q000737:chemistry; D044367:Phase Transition
D000178:Acrylamides; D003102:Colloids; D005782:Gels