Mechanical, Electronic, and Magnetic Properties of NiX2 (X = Cl, Br, I) Layers

Min Lu; Qiushi Yao; Chuanyun Xiao; Chengxi Huang; Erjun Kan

doi:10.1021/acsomega.9b00056

Mechanical, Electronic, and Magnetic Properties of NiX₂ (X = Cl, Br, I) Layers

ACS Omega. 2019 Mar 22;4(3):5714-5721. doi: 10.1021/acsomega.9b00056. eCollection 2019 Mar 31.

Authors

Min Lu¹, Qiushi Yao², Chuanyun Xiao¹, Chengxi Huang¹, Erjun Kan¹

Affiliations

¹ Department of Applied Physics and Institution of Energy and Microstructure, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, P. R. China.
² Department of Physics and Shenzhen Institute for Quantum Science and Technology, Southern University of Science and Technology, Shenzhen 518055, China.

Abstract

Since the recent experimental discovery of the CrI₃ and CrGeTe₃ monolayers, van der Waals (vdW) layered transition metal compounds have been recognized as promising candidates to realize 2D ferromagnetic (FM) semiconductors. However, until now, only limited compounds have been proposed to be ferromagnetic semiconductors. Here, on the basis of first-principles calculations, we report that the monolayer, Janus monolayer, and bilayer of NiX₂ (X = Cl, Br, I) are intrinsic 2D FM semiconductors. Our results show that exfoliation energy of the NiX₂ monolayer is smaller than that of graphene, and all studied NiX₂ layers show semiconducting band gaps. The predicted Curie temperature values for NiX₂ (X = Cl, Br, I) monolayers ranged from 120 to 170 K with Monte Carlo simulations. For the Janus monolayer, we found that the spin interaction shows a very strong magnetoelectric coupling under an external electric field. Furthermore, for the bilayer of NiX₂, our results show that the interlayer coupling is quite weak, indicating the possibility of tuning the magnetic coupling through external manipulations.