Experimental Observation of Continuous Melting into a Hexatic Phase

Abstract
This paper reports the results of an x-ray diffuse scattering study of the melting transition of monolayer xenon on the surface of single crystals of exfoliated graphite. It is found that the two-dimensional xenon solid melts into an orientationally ordered liquid (or hexatic) phase. The temperature dependence of the orientational correlations suggests that the hexatic phase exists as a consequence of the continuous melting process, not the substrate.