Capillary-Wave Roughening of Surface-Induced Layering in Liquid Gallium

Abstract

The temperature dependence of surface-induced atomic layering in liquid gallium has been investigated with x-ray reflectivity. The prominent layering peak at \(q_z\)=2.4 Å\(^{-1}\) decreases dramatically upon heating from 22 to 170\(^\circ\)C, but its width stays, unexpectedly, unchanged. The decrease is traced to the temperature dependence of capillary-wave induced surface roughness. The constant width indicates a temperature-independent layering decay length. The measured layering amplitudes are found to be significantly underestimated by existing theory and molecular simulations.