Co2Ge2Te6 shows an intrinsic ferromagnetic order, which originates from the superexchange interaction between Co and Te atoms, with a Curie temperature of 161 K. The Co2Ge2Te6 monolayer is half-metal, and the spin-β electron is a semiconductor with a gap of 1.311 eV. The Co2Ge2Te6 monolayer shows in-plane anisotropy, with a magnetic anisotropy energy (MAE) of −10.2 meV/f.u., and Te atoms contribute −9.94 meV/f.u. Moreover, the bilayer with AA- and AB-stackings has MAEs of −24.659 and −24.492 meV/.f.u., respectively. Most interestingly, bilayers present ferromagnetic half-metallicity independent of stacking orders. The multilayers (N ≥ 6) present ferromagnetic half metal, while magnetoelectronic properties are related with stacking patterns in thinner multilayers. Moreover, the magnetoelectronic properties of bulk are related with stacking patterns. The multilayers' magnetic orders are determined by the super–super exchange and weak van der Waals (vdW) interaction. Moreover, the Co2Ge2Te6 monolayer and multilayers show good dynamical and thermal stability. These findings could pave the way of application of intrinsic ferromagnetic Co2Ge2Te6 in the spintronics.
Two-dimensional (2D) intrinsic ferromagnetic (FM) materials play a crucial role in spintronics. Through a systematic research of the 2H-MoS2 bilayer (BL) with self-intercalation (SI) of Mo atom, we have discovered that SI can introduce a long-range magnetic order, as MoSI atoms lose electrons. The MoS2 BLs (MomSn) with self-intercalated Mo (MoSI) atoms show antiferromagnetic (AFM) order under a high concentration of MoSI atoms, where the direct exchange interaction dominates over the superexchange interaction. MomSn becomes half-metal (HM) with interlayer FM order after Mo's self-intercalation, under lower MoSI atom concentrations, independent of the stacking orders. Mo9S16-AA exhibits HM with FM order, with a corresponding Curie temperature (Tc) of 35 K. MomSn-AA and AB stackings with a lower concentration of MoSI atoms transform into half semiconductors (HSCs). Moreover, the magnetic anisotropy energies (MAEs) of Mo9S16-AA and AB stackings are −0.080 and −1.06 meV/f.u., suggesting that the magnetic easy axis (EA) of MomSn tends to the [100] direction, regardless of the stacking orders. However, the MAEs of MomSn-AA and AB stackings differ due to variations in the hybridization interaction between Mo's d orbitals. The formation energies of MomSn change with the chemical potential of S (μs) and the concentration of MoSI atoms. Furthermore, the formation energy (εf) monotonically increases as the concentration of MoSI monotonically increases. Additionally, MomSn with MoSI atoms could be synthesized under a higher chemical potential of Mo atom (μMo). The MomSn-AB stackings are always more stable than the AA stackings. Self-intercalated MomSn exhibits good dynamic and thermal stability at 300 and 600 K, respectively. These findings suggest a promising approach to introducing a modulated long-range FM order and electromagnetic properties into 2H-MoS2 and other transition metal dichalcogenides (TMDs).
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)