Mackinawite is a layer type iron chalogenide composed of edge-sharing FeS4 tetrahedral sheets stacked along the c-axis. It occurs naturally in anoxic environments, where it attenuates the mobility and bioavailability of toxic elements by adsorption and chemical reduction. Mackinawite also has been proposed as a reductive catalyst to convert CO2 into organic compounds. We examined the fundamental properties of this mineral using density functional theory (DFT). Geometry optimization along with a semi-empirical correction for the van der Waals interactions that stabilize the sheet stacking reproduced experimental structural parameters. Our results also predicted that the Fe ions have a magnetic moment, but that their magnetism is suppressed by spin fluctuations, which were then confirmed by photoemission spectroscopy.  This magnetic behavior is similar to that in the high-temperature superconductors with which mackinawite is isostructural, suggesting that it may be one of the simplest Fe-based superconductors.

New insights concerning mackinawite (tetragonal FeS) from DFT

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.