Tetra Point Wetting at the Free Surface of Liquid Ga-Bi

TL;DR

This study investigates the continuous wetting transition at the free surface of liquid Ga-Bi alloys, revealing the surface potential and the limited impact of thermal fluctuations on mean-field behavior.

Contribution

It provides the first detailed measurement of the surface potential and confirms the dominance of mean-field behavior in short-range wetting transitions at the tetra coexistence point.

Findings

Surface potential determined from temperature evolution

Thermal fluctuations do not significantly disrupt mean-field behavior

Wetting transition occurs at the tetra coexistence point

Abstract

A continuous surface wetting transition, pinned to a solid/liquid/liquid/vapor tetra coexistence point, is studied by x-ray reflectivity in liquid Ga-Bi binary alloys. The short-range surface potential is determined from the measured temperature evolution of the wetting film. The thermal fluctuations are shown to be insufficient to induce a noticeable breakdown of mean-field behavior, expected in short-range-interacting systems due to their $d_u=3$ upper critical dimensionality.