Progress in the studies of electronic and magnetic properties of layered MPX₃ materials (M: transition metal, X: chalcogen)

Abstract

The recent progress in the studies of 2D materials placed in front many experimental and theoretical works on the interesting class of materials, the so-called transition metal phosphorus trichalcogenides with structural formula MPX3 (M: transition metal, X: chalcogen). Here, the diversity in the M/X combination opens the possibility to tune the electronic and magnetic properties of these materials in a very wide range, resulting in many interesting physical phenomena followed by the promoting their use in different application areas. This review gives a timely overview of the recent progress in the fundamental studies of electronic structure and magnetic properties of MPX3 materials (M: Mn, Fe, Co, Ni, X: S, Se) focusing on the results obtained by density functional theory (DFT), Raman spectroscopy and electron spectroscopy methods. We pay close attention to the large amount of theoretical and experimental data giving critical analysis of the previously obtained results. It is shown how the systematic fundamental studies of the electronic and magnetic properties of MPX3 can help to understand the functionality of these interesting 2D materials in different applications, ranging from optoelectronics to catalysis.

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

“…These materials are also considered as a 3D basis for the preparation of their 2D counterpart in the form of mono- and multilayers. Among them, transition metal dichacogenides (MX 2 ; M = transition metal, X = chalcogen) − and phosphorus trichalcogenides (MPX 3 ) , are the focus of many experimental and theoretical works, giving much hope for application in different areas. − The mentioned transition-metal phosphorus trichalcogenides with a structural formula MPX 3 have a layered structure and crystallize within either the C 2/ m (X = S) or R 3̅ (X = Se) space group. ,, Every single layer is built on the basis of the honeycomb lattice formed by M 2+ ions, where every hexagon is centered by the P–P dimer forming the [P 2 X 6 ] 4– bipyramid with chalcogen layers sandwiching the layer of M 2+ ions, as shown in Figure a. The diversity in the M/X combination gives a wide range for band gaps and different magnetic configurations of MPX 3 .…”

“…The diversity in the M/X combination gives a wide range for band gaps and different magnetic configurations of MPX 3 . Following many experimental and theoretical works, MPX 3 are wide band gap antiferromagnetic (AFM) materials (band gaps spread in the range 1.2–3.5 eV), ,, where coupling between M 2+ magnetic moments is determined according to the Goodenough–Kanamori rule. − However, it was found that magnetic configurations and coupling strength between these magnetic moments can be tuned using adsorption or intercalation of different materials, by doping or alloying, thus opening perspectives for the application of these materials in spintronics and optical sensing. With respect to the studies of the electronic structure of MPX 3 , the existence of three different interactions in these materialsionic, covalent, and vdWmakes the description of the electronic structure of MPX 3 a very interesting and challenging task …”

“…These materials are also considered as a 3D basis for the preparation of their 2D counterpart in the form of mono-and multilayers. Among them, transition metal dichacogenides (MX 2 ; M = transition metal, X = chalcogen) 1−3 and phosphorus trichalcogenides (MPX 3 ) 4,5 are the focus of many experimental and theoretical works, giving much hope for application in different areas. 6−11 The mentioned transition-metal phosphorus trichalcogenides with a structural formula MPX 3 have a layered structure and crystallize within either the C2/m (X = S) or R3̅ (X = Se) space group.…”

“…With respect to the studies of the electronic structure of MPX 3 , the existence of three different interactions in these materials�ionic, covalent, and vdW�makes the description of the electronic structure of MPX 3 a very interesting and challenging task. 5 Among 3d-metal-based MPX 3 materials, FePS 3 and NiPS 3 attract attention because, despite the structural similarity, with respect to electronic structure they belong to two different classes of insulators. According to recent spectroscopic studies, FePS 3 is a Mott−Hubbard insulator (U dd < Δ) 12 with the top of the valence band formed by the hybrid Fe 3d/S 3sp states, whereas NiPS 3 is characterized as a charge-transfer insulator (U dd > Δ) 17,18 with the top of the valence band formed by the S 3sp states (U dd is the d−d correlation energy and Δ is the charge-transfer energy between d states of the metal and p states of the ligand 19 ).…”

“…6−11 The mentioned transition-metal phosphorus trichalcogenides with a structural formula MPX 3 have a layered structure and crystallize within either the C2/m (X = S) or R3̅ (X = Se) space group. 5,7,12 Every single layer is built on the basis of the honeycomb lattice formed by M 2+ ions, where every hexagon is centered by the P−P dimer forming the [P 2 X 6 ] 4− bipyramid with chalcogen layers sandwiching the layer of M 2+ ions, as shown in Figure 1a. The diversity in the M/X combination gives a wide range for band gaps and different magnetic configurations of MPX 3 .…”