Ising ferromagnetism and robust half-metallicity in two-dimensional honeycomb-kagome Cr2O3 layer

Abstract

In contrast to the current research on two-dimensional (2D) materials, which is mainly focused on graphene and transition metal dichalcogenide-like structures, studies on 2D transition metal oxides are rare. By using ab initio calculations along with Monte Carlo simulations and nonequilibrium Green’s function method, we demonstrate that the transition metal oxide monolayer (ML) of Cr2O3 is an ideal candidate for next-generation spintronics applications. 2D Cr2O3 has honeycomb-kagome lattice, where the Dirac and strongly correlated fermions coexist around the Fermi level. Furthermore, the spin exchange coupling constant shows strong ferromagnetic (FM) interaction between Cr atoms. Cr2O3 ML has a robust half-metallic behavior with a large spin gap of ~3.9 eV and adequate Curie temperature. Interestingly, an intrinsic Ising FM characteristic is observed with a giant perpendicular magnetocrystalline anisotropy energy of ~0.9 meV. Most remarkably, nonequilibrium Green’s function calculations reveal that the Cr2O3 ML exhibits an excellent spin filtering effect.

Valley splitting and magnetic anisotropy in two-dimensional VI3/MSe2 (M = W, Mo) heterostructures

“…, where V(r) is the spherical part of the effective potential within the PAW sphere, and L ˆand S âre the orbital and spin angular momentum values, respectively. 57,58 Fig. 6 shows the atom-resolved MAE of VI 3 /WSe 2 -III at strain values of À6%, À4%, À2%, 0%, 2%, 4%, and 6%.…”

High Curie Temperature and Intrinsic Ferromagnetic Half-Metallicity in Mn2X3 (X = S, Se, Te) Nanosheets

“…, (100), (010), and (001), for the Mn 2 X 3 nanosheets are examined and summarized in Table . It indicates that the Mn 2 Te 3 nanosheet possesses rather large MAE along the (100) direction up to −1.843 meV per Mn, which is much larger than that of previously reported NiAs-type Mn 2 X 3 (∼ −0.10 meV/Mn), Fe 2 Si (0.57 meV/Fe), MnSi (0.24 meV/Mn), Fe 2 CF 2 (−0.14 meV/Fe), Cr 2 O 3 (0.45 meV/Cr), and Co 2 Se 3 (−0.60 meV/Co), but smaller than that of Fe 3 B (4.13 meV/Fe) . The magnetic anisotropy along the x (100) and y (010) axes shows slight difference for Mn 2 Te 3 /Mn 2 Se 3 nanosheet, because the x and y directions are not symmetrically equivalent in the structure.…”

“…4 Unfortunately, the 2D ferromagnetic materials that have been realized in experiments to date, such as Cr 2 Ge 2 Te 6 , 5 CrI 3 , 6 and VI 3 7 are semiconductors while VSe 2 , 8 CrTe 2 , 9 and Fe 3 GeTe 2 10 are normal magnetic metals. Theoretically, although a number of 2D intrinsic FM HMs have been proposed, e.g., transition-metal (TM) dihydride, 11 NiAs-type transition-metal chalcogenides M n T n+1 (M = V, Cr, and Mn; T = S, Se, and Te; and n = 2, 3, and 4), 12 Fe 2 Si, 13 MnSi, 14 Cr 3 X 4 (X = S, Se, Te), 15 Fe 2 CF 2 , 16 and Cr 2 O 3 , 17 most of them possess only some of these three features, and candidates fulfilling all these requirements are rare. It is worth noting that 2D high-temperature FM HMs can also be induced by external modifications, such as graphene nanoribbons with edge modification, 18 strain-induced NbSe 2 , 19 and defectengineered T-TiSe 1.8 .…”

“…4 The half-metallic gaps are 1.78, 1.94, and 1.55 eV for Mn 2 X 3 (X = S, Se, Te) nanosheets, which are larger than that of previously reported NiAs-type Mn 2 X 3 (0.8−1.20 eV), 12 Fe 2 Si (0.50 eV), 13 MnSi (0.33 eV), 14 Fe 2 CF 2 (0.70 eV), 16 and Cr 2 O 3 (0.60 eV). 17 In summary, based on first-principles calculations, a series of intrinsic ferromagnetic (FM) half metals (HMs) Mn 2 X 3 (X = S, Se, Te) nanosheets are designed. Their Curie temperature is well above room temperature, from 718 to 820 K, which is desirable for making spintronic devices working at room temperature.…”

Liquid metals: an ideal platform for the synthesis of two-dimensional materials

“…Other potential applications for the materials discussed in this tutorial review include photocatalysis, 49 biosensors and 131 spintronics, 132 where the developed liquid metal-based approaches could provide a pathway to new 2D materials that may be suitable for these applications. Overall, liquid metal derived 2D materials hold the potential to supplement the already existing family of nanoscale materials while offering the capability to create 2D materials with reliable thickness and extraordinarily large lateral dimensions.…”