Fig. 3: XRD measurements.

X-ray scattering intensities in the (h0l) plane of reciprocal space measured by means of single crystal X-ray diffraction on (a, c) LiVO₂ and (b, d) Li_0.91VO₂. The detector background offset amounts to 32 counts; the intensities for both compounds are presented on the same unit cell (without any doubling of c); intensity scale is plotted with a logarithmic color scheme. For the single crystal of Li_0.91VO₂, the superstructure reflections (at h = −4) are well-separated with peak intensities reaching the background level between two reflections. l-scans across the superstructure reflections at h = −4 are shown in (c) for LiVO₂ (red circles) and in (d) for Li_0.91VO₂ (blue dots); brown line: detecor background offset. In (d), the light gray shaded area indicates a scan across the fundamental Bragg reflections (with intensities divided by 50) and solid lines indicate gaussian fits in order to obtain the peak widths (FWHM). In (c), the intensity difference of the intensities of the LiVO₂ sample and of the intensities of the Li_0.91VO₂ sample weighted by 45% is shown. This suggests a doubling of the unit cell in c-direction for LiVO₂ (see text).