Commensurate-incommensurate and rotational transitions of monolayer xenon on single-crystal graphite.

Abstract

We have studied the structures and transitions of high-density xenon monolayers on single-crystal graphite using high-resolution synchrotron x-ray diffraction techniques. In contrast to the previous x-ray experiment, we find that at low temperatures, the xenon has a commensurate $\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}R30\ifmmode^\circ\else\textdegree\fi{}$ structure for a broad range of coverages. With decreasing temperature the novel reentrant sequence: aligned\ensuremath{\rightarrow}rotated\ensuremath{\rightarrow}aligned, occurs; this sequence is followed by a first-order incommensurate-commensurate transition.