LITHIUM INTERCALATION INTO THE TETRADYMITE-TYPE SELENIDES SULFIDES BI2SE3-XSX

The reaction rate of Li intercalation into Bi2Se3-xSx single crystals (x = 0, 0.025 and 0.5) increases with an increasing sulfur content in the crystals. This effect has been explained qualitatively by a change in the bond polarity in the Bi2Se3 due to the substitution of seleniu m atoms by sulfur atoms. This substitution results in a change in the electron density distribution and thus also in the width of the van de r Waals gap between the structural layers, responsible for the course of intercalation. This explanation is supported by a quantum-chemical calculation of the charges on the atoms of the Bi2Se3-xSx lattice mani festing and increase in the negative charge on Se atoms with an increa sing value of x.