Prediction of single-atom-thick transition metal nitride CrN4 with a square-planar network and high-temperature ferromagnetism

Article

关键词: EXFOLIATION;   

DOI  :  10.1103/PhysRevB.106.125421

来源: SCIE

【 摘 要 】

Single-atom-thick two-dimensional (2D) materials such as graphene usually have a hexagonal lattice while the square-planar lattice is uncommon in the family of 2D materials. Here, we demonstrate that single-atom-thick transition metal nitride CrN4 monolayer is a stable free-standing layer with a square-planar network. The stability of square-planar geometry is ascribed to the combination of N=N double bond, Cr-N coordination bond, and pi-d conjugation, in which the double pi-d conjugation is rarely reported in previous studies. This mechanism is entirely different from that of the reported 2D materials, leading to lower formation energy and more robust stability than the synthesized g-C3N4 monolayer. On the other hand, the CrN4 layer has a ferromagnetic (FM) ground state, in which the FM coupling between two Cr atoms is mediated by electrons of the half-filled large pi orbitals from pi-d conjugation. The high-temperature ferromagnetism in CrN4 monolayer is confirmed by solving the Heisenberg model with the Monte Carlo method.

【 授权许可】

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