Mo cluster formation in the intercalation compound LiMoS2

In the past it has been claimed that lamellar molybdenum disulfide MoS2 undergoes a deep structural transformation upon lithium intercalation. In the absence of accurate x-ray diffraction data, the structure of LiMoS2 is not clearly known, even if recent x-ray absorption spectroscopy results indicate a cluster formation of molybdenum. First principle calculations have been performed in using the full-potential linearized augmented plane wave method. They predict a cluster formation mode in the so-called ''diamond-chain'' scheme and an ABAB sulfur stacking mode. This proposed structure is in agreement with all available experimental results. Calculations indicate that a charge-density-wave phenomenon would be at the origin of such a cluster formation.