title: Melting of colloidal crystal films.
abstract: We study melting mechanisms in single and polycrystalline colloidal films composed of diameter-tunable microgel spheres with short-ranged repulsive interactions and confined between two glass walls. Thick films (>4 layers), thin-films (≤4 layers), and monolayers exhibit different melting behaviors. Thick films melt from grain boundaries in polycrystalline solid films and from film-wall interfaces in single-crystal films; a liquid-solid coexistence regime is observed in thick films but vanishes at a critical thickness of 4 layers. Thin solid films (2 to 4 layers) melt into the liquid phase in one step from both grain boundaries and from within crystalline domains. Monolayers melt in two steps with a middle hexatic phase.
authors.affiliation: Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Peng
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: A M
authors.initials: AM
authors.lastname: Alsayed
authors.forename: A G
authors.initials: AG
authors.lastname: Yodh
authors.forename: Y
authors.initials: Y
authors.lastname: Han