Screening and Design of Novel 2D Ferromagnetic Materials with High Curie Temperature above Room Temperature

Abstract

Two-dimensional (2D) intrinsic ferromagnets with high Curie temperature (T C) are desirable for spintronic applications. Using systematic first-principles calculations, we investigate the electronic and magnetic properties of 22 monolayer 2D materials with layered bulk phases. From these candidates, we screen out five ferromagnetic monolayer materials belonging to three types of structures: type i (ScCl, YCl, LaCl), type ii (LaBr2), and type iii (CrSBr). Type i is a kind of metallic ferromagnetic material, whereas LaBr2 and CrSBr of type ii and iii are small-bandgap ferromagnetic semiconductors with T C near room temperature. Moreover, the ferromagnetic CrSBr monolayer possesses a large magnetic moment of ∼3 μB per Cr atom, originating from its distorted octahedron coordination. The robust ferromagnetism of the CrSBr monolayer is ascribed to the halogen-mediated (Cr–Br–Cr) and chalcogen-mediated (Cr–S–Cr) superexchange interactions; then, an isoelectronic substitution strategy is proposed to tailor the magnetic coupling strength. Hence, monolayer structures of CrSI, CrSCl, and CrSeBr with notably enhanced Curie temperature up to 500 K as well as favorable formation energy are designed. The moderate interlayer binding energy and high T C make these monolayer ferromagnetic materials feasible for experimental synthesis and attractive as 2D spintronic devices.

Computational Prediction of the Low‐Temperature Ferromagnetic Semiconducting 2D SiN Monolayer

“…The hotter topic in the scientific community is atomically thin materials with ferromagnetic properties. Recent theoretical predictions and experimental syntheses of ferromagnetic flat materials opened up new possibilities for their use in spintronic devices. Several years ago, it was theoretically predicted that a cis ‐semi‐hydrated graphene sheet ( cis ‐C 2 H) is ferromagnetic .…”

High-throughput discovery of high Curie point two-dimensional ferromagnetic materials

“…The python module ASE 39 has also been used to parse the input structure files. To ensure the reliability and coverage of the pymatgen generated spin configurations, we manually verify that the code-generated spin configuration set almost always includes all heuristics-based configurations reported in the literature [9][10][11][12][13][14] . Often, the code generates even more unexplored but symmetrically valid configurations that we leverage to include a higher number of neighbour interactions for a more accurate prediction of the T C .…”

“…However, the more recent discovery of even room-temperature ferromagnetism in monolayer VSe 2 7 and MnSe 2 8 has been possible as the strong magnetocrystalline anisotropy of these 2D materials lifts the Mermin-Wanger restriction. So far, a plethora of 2D ferromagnetic (FM) materials [9][10][11][12][13][14] have been computationally predicted, including a few general-purpose 2D materials databases [15][16][17] containing hundreds to thousands of entries. However, none of these databases contain the most crucial parameter for 2DFM materials relevant for practical applications: the transition temperature or Curie point (T C ).…”

Computational Design of One‐Dimensional Ferromagnetic Semiconductors in Transition Metal Embedded Stannaspherene Nanowires

“…Unfortunately, up to now, the realization of such materials is rather scarce, and still challenges the physical chemistry world. In two dimension (2D), although a number of ferromagnetic semiconductors are predicted theoretically, only two, i.e ., CrGeTe 3 and CrI 3 , have been confirmed by experiments . To overcome this challenge, a general method for developing 2D ferrimagnetic organometallic semiconductors has been proposed recently .…”