Intertwined electronic and magnetic structure of the van-der-Waals antiferromagnet Fe2P2S6

Abstract

Many unusual and promising properties have been reported recently for the transition metal trichalcogenides of the type MPS3 (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 Fe2P2S6, giant linear dichroism among others. Here we conduct a detailed investigation of the electronic structure of Fe2P2S6 using angle-resolved photoemission spectroscopy, q-dependent electron energy loss spectroscopy, optical spectroscopies and density functional theory. Fe2P2S6 is a Mott insulator with a gap of Egap ≈ 1.4 eV and zigzag antiferromagnetism below TN = 119 K. The low energy excitations are dominated by Fe 3d 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 Fe2P2S6 and related materials.

Electronic Correlations in Multiferroic Van der Waals CuCrP2S6: Insights from X-ray Spectroscopy and DFT

“…For example, near-edge X-ray absorption fine structure (NEXAFS) and resonant photoelectron spectroscopy (ResPES) allowed one to assign MnPX 3 and FePX 3 to the class of Mott–Hubbard insulators, − NiPS 3 to the class of charge-transfer insulators, , whereas CoPS 3 has a mixed character of the insulating state . It is interesting that mixed Fe x Ni y PS 3 alloys demonstrate a dual character of the insulating state in their electronic structure pointing to very weak (if any) hybridization of Fe- and Ni-derived electronic states. , Recent angle-resolved photoelectron spectroscopy experiments on different MPX 3 materials demonstrate a rather good agreement with available calculated band structures, allowing us to identify partial elemental and orbital contributions in the electronic structure. ,− …”

Electronic Correlations in FexNiyPS3 Van der Waals Materials: Insights from Angle-Resolved Photoelectron Spectroscopy and DFT

“…The detailed electronic structure E ( k ) of MPX 3 using angular-resolved photoelectron spectroscopy (ARPES) was recently addressed in a series of works for CoPS 3 and FePS 3 , , and quite good agreement was found between experimental data and theoretical results obtained within the density functional theory (DFT) approach using HSE06 and PBE+ U ( U = 1.9 eV) functionals, respectively. However, the respective data for NiPS 3 and mixed Fe x Ni y PS 3 vdW alloys are not available.…”

“…At the same time Fe 1−x Ni x PS 3 alloys demonstrate the dual character of the electronic structure, simultaneously combining both insulating characters pointing to the absence of the hybridization of the electronic states from Fe 2+ and Ni 2+ ions. 20 It is also worthwhile to mention that both MPX 3 materials have different magnetic states: FePS 3 is Ising AFM with zigzag (zAFM) order of magnetic moments and T N = 118 K ; 21,22 NiPS 3 is XXZ zAFM with T N = 158 K. 23 The detailed electronic structure E(k) of MPX 3 using angular-resolved photoelectron spectroscopy (ARPES) was recently addressed in a series of works for CoPS 3 24 and FePS 3 , 25,26 experimental data and theoretical results obtained within the density functional theory (DFT) approach using HSE06 and PBE+U (U = 1.9 eV) functionals, respectively. However, the respective data for NiPS All studied MPX 3 layered compounds were synthesized using the chemical vapor transport (CVT) method as discussed is the Methods section and then were routinely characterized using different experimental methods as discussed elsewhere.…”