First-Principles Study of the Ferromagnetic Properties of Cr₂CO₂ and Cr₂NO₂ MXenes

Abstract

Massive attention has been paid to MXenes due to their intriguing properties and potential diverse applications. Extensive studies using first-principles calculations on the electronic structures of MXenes Cr 2 CO 2 and Cr 2 NO 2 were performed in this paper. Based on the accurate Heyd–Scuseria–Ernzerhof (HSE) calculations, Cr 2 CO 2 is clarified to be a ferromagnetic semiconductor; meanwhile, Cr 2 NO 2 is a half-metallic material, which is consistent with previous results. In particular, by analyzing the contribution of the orbitals to the band structures and density of states, the basic mechanism of ferromagnetism was analyzed in detail. Our theoretical work might promote the spintronics study and application of Cr-contained MXenes.

Effect of oxygen termination on the interaction of first row transition metals with M2C MXenes and the feasibility of single-atom catalysts

“…54 Alternatively, we found that the MXenes composed of d 4 -(Mo and W) metals prefer BABCB stacking, which is consistent with previous studies. [57][58][59] Here, it should be noted that Tan et al 59 claimed that BABCB stacking was preferred by Cr 2 CO 2 . This result may be attributed to the use of a different functional (DFT + U with U ¼ 4 eV) to initially optimize the crystal structures, which were later rened with a hybrid density functional.…”

Theoretical Study on the Electronic Structure and Magnetic Properties Regulation of Janus Structure of M’MCO2 2D MXenes

“…There are four possible configurations for O atoms absorbed on the M atom [ 51 ]: (a) O atoms located right above the M atoms (top sites); (b) O atoms located at the hollow sites of adjacent C atoms (hcp sites); (c) O atoms located at the hollow sites of contralateral M atoms (fcc sites); (d) on the one side, O atoms are at fcc sites, and on the other side, O atoms are at the hcp sites. According to previous research by Tan [ 52 ] and Wang [ 53 ], (b) configuration is stable for CrMnCO 2 and Cr 2 CO 2 and (c) configuration is stable for VCrCO 2 , VMnCO 2 , V 2 CO 2 , and Mn 2 CO 2 . So, we selected those configurations for the following calculations.…”

Strain Effects on the Two-Dimensional Cr2N MXene: An Ab Initio Study

“…52 53 Then, the MXene Cr 2 N has a centered honeycomb (T) structure where the N atoms are in-between two layers of the hexagonal lattice of Cr atoms. 54 The interplanar distance is 1.14 Å, and the Cr–N bonds have a distance of 2.12 and 2.06 Å, for more details see Figure S1 in Supporting Information. Figure 1 displays a top and side view of the crystal structure of the unstrained Cr 2 N MXene.…”

“…The Cr atoms are located at (1/3, 2/3, z ) and (2/3, 1/3, −z) on the 2 d Wyckoff sites; meanwhile, the N atom is located at (0, 0, 0) on the 1 a Wyckoff site Then, the MXene Cr 2 N has a centered honeycomb (T) structure where the N atoms are in-between two layers of the hexagonal lattice of Cr atoms . The interplanar distance is 1.14 Å, and the Cr–N bonds have a distance of 2.12 and 2.06 Å, for more details see Figure S1 in Supporting Information.…”