Figure 2
Crystal structure determination of the ferecrystals (PbSe)1.14(NbSe2)n with n = 1, 2 and 3.
(a) XRD scans (Obs.) showing the periodically layered structure of the ferecrystals. A Rietveld refinement (Calc.) was performed to determine atomic plane distances along the stacking direction. The difference (Diff.) between observed and calculated data is also shown. (b) Structure models of the (PbSe)1.14(NbSe2)n ferecrystals. The repeat unit thickness c and the distances d1, d2 and d3 between atomic planes along the stacking direction are indicated. A van der Waals (v.d.W.) gap between the NbSe2 layers is present and is marked for n = 3 exemplarily. (c) In-plane XRD scans with peaks, which can be indexed to a hexagonal (NbSe2) and a square (PbSe) basal plane in accordance with the bulk structures. The peaks can be indexed as hk0 separately for NbSe2 (black) and PbSe (gray). Dashed lines indicate the peak positions. (d) Structure models of a PbSe and a NbSe2 projected onto the layer plane. Unit cells are indicated by dashed lines.
