Fig. 1: Atomic structure of the single-layered flattened NbSe2 nanotube encapsulated within CNT.
a Atomic-resolved cross-sectional BF images of single-layered flattened NbSe2 nanotube. b Enlarged image of the region framed in yellow in a. c the corresponding optimized atomic models, where the gold and blue atoms represent Selenium and Niobium, respectively. Therein, the red and blue arrows indicate the corresponding images obtained by projection along the major- and minor-axis directions, respectively. d Atomic-scale annular dark field (ADF) images with their corresponding simulation and model of NbSe2 flat tube viewed along the minor-axis direction. e–g ADF images (e), high-magnification images (f), and image simulations (g) of the AB-stacked NbSe2 flat tube, which shows a 2H phase in the major-axis direction. h–j ADF images and corresponding simulation of AA-stacked NbSe2 flat tube with filled honeycomb structure, indicate its 1T phase along the major-axis direction. k, l Schematic representation of the AB (k) and AA (i) stacking modes that generate 2H and 1T phase, respectively. The x, y, and z axis correspond to the fragment of the NbSe2 sheet used to model the flat nanotube. Scale bars: 2 nm for a, 1 nm for b, d, e, h, 200 pm for (f, i).
