Fig. 1: Surface melting of an attractive colloidal glass.
a Snapshots of a glass surface at temperatures ΔT = 4.5 K. The color code represents the local Voronoi area. The dashed horizontal line indicates the location of \({z}_{{{{{{{{\rm{sat}}}}}}}}}^{\varphi }\) as defined in (f). The scale bar is 50 μm. The origin of the z-axis has been defined by \({z}_{{{{{{{{\rm{sat}}}}}}}}}^{\varphi }\) for 4.5 K. b–e Typical zoom-in snapshots of the glass surface area (see dashed rectangular area in (a)) at different temperatures: ΔT = 2.5 K (b), 3.5 K (c), 4.5 K (d), 5.5 K (e). The scale bar is 15 μm. f Depth-resolved particle area fraction for different ΔT near the saturation and over the entire z range (inset). Dashed lines indicate \({z}_{{{{{{{{\rm{sat}}}}}}}}}^{\varphi }(\Delta T)\) where the corresponding area fractions reach 99.5% of the corresponding φsat. To compare profiles with different temperatures, \({z}_{{{{{{{{\rm{sat}}}}}}}}}^{\varphi }(\Delta T=2.5\,{{{{{{{\rm{K}}}}}}}})\) was chosen as the origin of the z-axis.
