Large‐Spin‐Gap Nodal‐Line Half‐Metal and High‐Temperature Ferromagnetic Semiconductor in Cr₂X₃ (X=O,S,Se) Monolayers

Abstract

Two‐dimensional (2D), high‐temperature, half‐metal ferromagnetic semiconductors with large spin gap and topological band structures are highly desirable for novel nanoscale spintronic applications. A family of stable 2D honeycomb‐Kagome Cr2X3 (X=O,S,Se) monolayers is proposed through first‐principles calculations. Buckled Cr2O3 is a ferromagnetic semiconductor with large out‐of‐plane magnetocrystalline anisotropy energy and a predicted Curie temperature of 332 K under moderate biaxial tensile strain. Planar Cr2S3 and Cr2Se3 are ferromagnetic half‐metals with mirror‐symmetry‐protected nodal lines for spin‐down channel and large direct gap (4.59 and 4.76 eV) for spin‐up channel. The Fermi velocities for Cr2S3 and Cr2Se3 are 2.1×105 and 1.5×105 m s−1, respectively, which is comparable with that of silicene, 5.3 × 105 m s−1. Their Berezinskii–Kosterlitz–Thouless transition temperatures are determined to be as high as 445 and 695 K. In addition, their half metallicity can be well maintained on h‐BN nanosheets and is immune to chemical perturbation and mechanical strain. Its fascinating magnetic properties and topological nodal lines render 2D Cr2X3 (X=O,S,Se) suitable for novel spintronic devices and exotic quantum applications.

A Universal Fe/N Incorporated Graphdiyne for Printing Flexible Ferromagnetic Semiconducting Electronics

“…However, the lower Curie temperature ( T c ) forces people to expend a significant amount of effort to explore room-temperature ferromagnetism. Among various material systems, carbon materials , represented by graphene and graphdiyne (GDY) exhibit advantages on spin diffusion, facile preparation, and easy chemical modification, especially suitable for the characteristics of flexible devices and other new electronic devices, which have been recognized as promising candidates for ferromagnetic semiconductors. − A series of methods have been developed to introduce a magnetic moment, − such as the most effective means through transition-metal doping to induce ferromagnetism. − Determining how to develop more straightforward methods to quickly realize the coexistence of semiconductivity and ferromagnetism based on such materials has become crucial. Meanwhile, for the practical application of such materials, it is necessary to meet the printing process requirements of large-area flexible devices while maintaining material properties’ stability during the device preparation process, which also needs to be urgently explored.…”

Theoretical simulation and design of two-dimensional ferromagnetic materials

“…Cr 2 I 3 X 3 (X=Br, Cl)单层也是一种间接带隙半导体, 具有本征的 铁磁性 [67] . Cr 2 O 3 单层在双轴拉伸应变下具有较大的面 外MAE, 其基于伊辛模型的T C 理论值高达332 K [68] . 值 得注意的是, 最近对范德华层状块体CrOCl和CrSBr进 行的重复实验研究表明, 它们在空气中能够稳定存在, 且剥离成原子层厚度的可能性很大 [69,70] .…”

Thermoelectric, spin-dependent optical and quantum transport properties of 2D half-metallic Co2Se3

“…36–39 Using ab initio studies, the half-metal ferromagnetism properties of 2D TcS 2 nanosheets ( T C > 800 K), 2D Co 2 S 2 ( T C = 404 K), Cr 2 Se 3 ( T C = 480 K), Cr 2 S 3 ( T C = 420 K), and Cr 2 Te 3 ( T C = 510 K) monolayers and 2D Cr 2 O 3 monolayer ( T C = 332 K) have been reported. 40–43…”

“…[36][37][38][39] Using ab initio studies, the half-metal ferromagnetism properties of 2D TcS 2 nanosheets (T C 4 800 K), 2D Co 2 S 2 (T C = 404 K), Cr 2 Se 3 (T C = 480 K), Cr 2 S 3 (T C = 420 K), and Cr 2 Te 3 (T C = 510 K) monolayers and 2D Cr 2 O 3 monolayer (T C = 332 K) have been reported. [40][41][42][43] One of the 2D-TMCs, which has unique properties, is the Co 2 monolayer exhibits half-metal ferromagnetism with high Curie temperature and superior mechanical flexibility. 3,44 This paper investigates the thermoelectric, spin-dependent optical and quantum transport properties of 2D Co 2 Se 3 .…”