fig1

Figure 1. (A) The structures and (B) projected Crystal Orbital Hamilton Population (-pCOHP) of SnSe and NaSn₂SbSe₄. The Electron Localization Function (ELF) analysis of (C) SnSe and (D) NaSn₂SbSe₄, respectively; (E) The calculated integrated crystal orbital bond index (ICOBI) for the Sn-Se bond in SnSe and the Sb/Na/Sn-Se bonds in NaSn₂SbSe₄.