Electronic structure of tin monochalcogenides from SnO to SnTe

The family of tin monochalcogenides $(\mathrm{Sn}X,$ $X=\mathrm{O},$ S, Se, or Te) is calculated in order to point out trends in properties. Electronic structures are calculated from density functional theory pseudopotential and tight-binding theories. Resulting densities of states present similar features. Calculated $\mathrm{Sn}(5s)$ populations and charge-density contours are shown to be consistent with the presence of a lone pair. The lone pair is also studied from M\"ossbauer spectroscopy, which points out the particular case of SnO.