Exfoliated single molecular layers of Mn_0.8PS₃and Cd_0.8PS₃

The layered compounds MnPS₃and CdPS₃were exfoliated to form single molecular layers of Mn_0.8PS₃and Cd_0.8PS₃in suspension in water by ion exchange. The x-ray diffraction patterns of the two single-layer suspensions showed profound differences in some of the Bragg peaks, and we demonstrated that the differences are not due to the quality or size of the single layers, but are caused by structure factor modulations of the Warren tail for two-dimensional systems. We also demonstrated that the Cd or Mn vacancies generated in the exfoliation process are not ordered at long range, in contrast to an earlier report of vacancy ordering on intercalated MnPS₃.