Intertwined electronic and magnetic structure of the van-der-Waals antiferromagnet Fe2P2S6
A. Koitzsch, Tom Klaproth, S. Selter, Yuliia Shemerliuk, Saicharan Aswartham, Oleg Janson, B. Büchner, M. Knupfer
Abstract
Abstract Many unusual and promising properties have been reported recently for the transition metal trichalcogenides of the type M PS 3 ( M = V, Mn, Fe, Ni ...), such as maintaining magnetic order to the atomically thin limit, ultra-sharp many-body excitons, metal-insulator transitions and, especially for Fe 2 P 2 S 6 , giant linear dichroism among others. Here we conduct a detailed investigation of the electronic structure of Fe 2 P 2 S 6 using angle-resolved photoemission spectroscopy, q -dependent electron energy loss spectroscopy, optical spectroscopies and density functional theory. Fe 2 P 2 S 6 is a Mott insulator with a gap of E gap ≈ 1.4 eV and zigzag antiferromagnetism below T N = 119 K. The low energy excitations are dominated by Fe 3 d states. Large and sign-changing linear dichroism is observed. We provide a microscopic mechanism explaining key properties of the linear dichroism based on the correlated character of the electronic structure, thereby elucidating the nature of the spin-charge coupling in Fe 2 P 2 S 6 and related materials.