Carrier Doping Modulates 2D Intrinsic Ferromagnetic Mn₂Ge₂Te₆ Monolayer, High Curie Temperature, Large Magnetic Crystal Anisotropy

Abstract

Mn2Ge2Te6 shows intrinsic ferromagnetic (FM) order, with a Curie temperature (T c) of 316 K. The FM order origins from superexchange interaction between Mn and Te atoms. Mn2Ge2Te6 is half-metal (HM), and spin-β electron is a semiconductor with a gap of 1.462 eV. Mn2Ge2Te6 tends to show in-plane anisotropy (IPA), with a magnetic anisotropy energy (MAE) of −13.2 meV/f.u. Mn2Ge2Te6 shows good dynamical and thermal stability. Moreover, Mn2Ge2Te6 presents good ferromagnetic and half-metallic stability under charge doping. The carrier doping could effectively tune magnetic and electronic properties. Specifically, the magnetic moment, exchange parameter, and MAE could be efficiently tuned. The total magnetic moment changes linearly with charge doping. The magnetic exchange parameters could be controlled by the doping carriers. The carrier doping could modulate MAE to −18.4 (+0.4 e), −0.85 (−1.6 e), and 1.31 (−2.4 e) meV/f.u., by changing hybridization between Te atom’s p y and p z orbitals. Mn2Ge2Te6 with intrinsic ferromagnetism, high tunable MAE, good stability of ferromagnetism, and half-metallicity could help researchers to investigate its wide application in electronics and spintronics.

Tailing the Magnetoelectric Properties of Cr2Ge2Te6 by Engineering Covalently Bonded Cr Self-Intercalation: Ferromagnetic Half-Metal

“…111-AA-2 and 111-AA-SI-2 have a D 3 point group, while 111-AB-2 and 111-AB-SI-2 have a C 3 point group. As a result, the energy difference Δ E 0 is independent of the in-plane azimuthal angle ϕ, ,, and the energies with EA along the [100] and [010] directions are the same . In consequence, K 4 equals 0, as shown in Figures S11b,c and a,b.…”

“…Compared with k 2 and k 3 , k 1 is much larger, which is similar to CGT, as shown in Figure S11b. According to Figure b, MAE could be calculated by the following equation M A E = E false[ 100 false] − E false[ 001 false] The corresponding MAEs of CGT with 111-AA-2 and 111-AB-2 stackings are 1.80 and 1.91 meV/f.u., as shown in Figure S11c, respectively. The positive MAE implies EA is along the out-of-plane direction, that is, parallel to the c -axis, which indicates perpendicular magnetic anisotropy (PMA), as shown in Figure S11a .…”

“…In all kinds of modified methods, intercalation is a useful approach to controlling vdW materials’ properties, such as topological properties, photonics, optoelectronic properties, , thermoelectric properties, , energy storage, , catalytic properties, and magnetoelectric properties. ,,,− Apart from foreign atoms, the native atoms could also work as intercalants . This phenomenon is called self-intercalation, which has attracted much attention.…”

“…Most 2D materials are nonmagnetic materials, , as long-range magnetic order is prohibited by the strong fluctuations at finite temperature in 2D materials . Recently, 2D van der Waals (vdW) magnetic materials, , such as CrI 3 (MI 3 ), − Fe 3 GeTe 2 , , VS­(Se) 2 , − VSeTe, , and CGT, − have attracted much attention. Interlayer magnetic coupling has been confirmed to play an important role in modulating the magnetoelectric properties of magnetic vdW materials.…”

Spin-gapless van der Waals heterostructure for spin gating through magnetic injection devices

“…The Curie temperature of Cr 2 NOF was higher than that of some recently proposed 2D magnetic materials, such as CrI 3 , 47 FeX 3 (X = F, Cl, and I) 48 Mn 2 Ge 2 Te 6 , 49 but slightly lower than that of FeBr 3 . 50 In addition, based on molecular dynamics simulation, it was found that the magnetic state of Cr 2 NOF can exist at room temperature. Here, in order to illustrate the applications of the Janus MXene, we used a Cr 2 NOF/2DH (graphene, BN, MoS 2 , GaN) bilayer as an example to discuss the effect of the contact with different 2DHs on the electronic properties.…”