Fig. 6: Proposed microscopic picture of stacking-selective self-intercalation.
From: Direct visualization of stacking-selective self-intercalation in epitaxial Nb1+xSe2 films
a The difference in DFT total energies per formula unit between 180°- and 0°-stacked bilayer Nb1+xSe2 with varying concentrations of Nb intercalants at the interstitial octahedral sites. A negative (positive) value of E(180°) – E(0°) implies that the 180° (0°) structure is more stable and is indicated by the red (blue) color of the data points and shaded regions. b DFT-computed change in total energy upon intercalation into the octahedral voids of 180°- and 0°-stacked bilayer Nb1+xSe2, as shown in the insets. c, d Proposed phase diagrams for Nb1+xSe2 grown via hPLD and chemical vapor transport (CVT), respectively. The hPLD-grown films lie at the phase boundary between 0° and 180° stacking, whereas our CVT-grown crystals have not reached the second 180°-stacked phase.
