Apparent Ferromagnetism in Exfoliated Ultrathin Pyrite Sheets

Experimental evidence for ferromagnetic ordering in isotropic atomically thin two-dimensional crystals has been missing until a bilayer Cr2Ge2Te6, and three-atom thick monolayer CrI3 are shown to retain at finite temperatures. Here, we demonstrate successful isolation of non-van der Waals type ultra-thin nanosheet FeS2 derived from naturally occurring pyrite mineral (FeS2) by means liquid-phase exfoliation. Structural characterizations imply that (111) oriented sheets predominant is supported theoretically density functional theory surface energy calculations. Spin-polarized calculations further predicted sheet stable ground state different its diamagnetic bulk counterpart. This theoretical finding evaluated experimentally employing low temperature superconducting quantum interference device measurements observed an anomalous kind behavior.